review article a review of removal of pollutants from...

Review ArticleA Review of Removal of Pollutants from WaterWastewaterUsing Different Types of Nanomaterials

M T Amin A A Alazba and U Manzoor

Alamoudi Water Research Chair King Saud Universtiy PO Box 2460 Riyadh 11451 Saudi Arabia

Correspondence should be addressed to M T Amin mtaminksuedusa

Received 2 January 2014 Revised 3 March 2014 Accepted 3 March 2014 Published 23 June 2014

Academic Editor A G Barbosa de Lima

Copyright copy 2014 M T Amin et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

The rapidly increasing population depleting water resources and climate change resulting in prolonged droughts and floods haverendered drinking water a competitive resource in many parts of the world The development of cost-effective and stable materialsand methods for providing the fresh water in adequate amounts is the need of the water industry Traditional waterwastewatertreatment technologies remain ineffective for providing adequate safe water due to increasing demand of water coupled withstringent health guidelines and emerging contaminants Nanotechnology-based multifunctional and highly efficient processesare providing affordable solutions to waterwastewater treatments that do not rely on large infrastructures or centralized systemsThe aim of the present study is to review the possible applications of the nanoparticlesfibers for the removal of pollutants fromwaterwastewater The paper will briefly overview the availability and practice of different nanomaterials (particles or fibers) forremoval of viruses inorganic solutes heavy metals metal ions complex organic compounds natural organic matter nitrate andother pollutants present in surface water ground water andor industrial water Finally recommendations are made based on thecurrent practices of nanotechnology applications in water industry for a stand-alone water purification unit for removing all typesof contaminants from wastewater

1 Introduction

Water has a broad impact on all aspects of human life includ-ing but not limited to health food energy and economy Inaddition to the environmental economic and social impactsof poor water supply and sanitation [1ndash4] the supply of freshwater is essential for the safety of children and the poor [5 6]It is estimated that 10ndash20 million people die every year dueto waterborne and nonfatal infection causes death of morethan 200 million people every year [7] Every day about5000ndash6000 children die due to the water-related problemof diarrhea [8 9] There are currently more than 078 billionpeople around the world who do not have access to safewater resources [10] resulting in major health problems It isestimated that more than one billion people in the world lackaccess to safe water and within couple of decades the currentwater supply will decrease by one-third

The portion of total run-off which constitutes stablerun-off flow is considered as the freshwater resource upon

which humans depend This stable fresh water flow has beenestimated at 12500ndash15000 km3 per year [11 12] from which4000 km3 per year is considered to be the total freshwater forirrigation industry and domestic purposes [13] and which isestimated to increase to a range of 4300ndash5000 km3 per year in2025 [14ndash16] Alternatively only accessible fresh water is 05of the worldrsquos 14 billionKm3 of water which is furthermorepoorly distributed across the globe [17]

There is limited possibility of an increase in the supplyof fresh water due to competing demands of increasing pop-ulations throughout the world also water-related problemsare expected to increase further due to climate changes anddue to population growth over the next two decades [18]It is estimated that worldwide population will increase byabout 29 billion people between now and 2050 (accordingto UNrsquos average projections) [15] Shortage of fresh watersupply is also a result of the exploitation of water resourcesfor domestic industry and irrigation purposes in many

Hindawi Publishing CorporationAdvances in Materials Science and EngineeringVolume 2014 Article ID 825910 24 pageshttpdxdoiorg1011552014825910

2 Advances in Materials Science and Engineering

parts of the world [19] The pressure on freshwater resourcesdue to the increasing worldrsquos demand of food energy andso forth [20 21] is increasing more and more due topopulation growth and threats of climate change Pollutingsurfaceground water sources is another cause of reducedfresh water supplies [22ndash24] Aquifers around the worldare depleting and being polluted due to multiple problemsof saltwater intrusion soil erosion inadequate sanitationcontamination of groundsurface waters by algal bloomsdetergents fertilizers pesticides chemicals heavy metalsand so forth [25ndash28]

The occurrence of newemerging microcontaminants(eg endocrine disrupting compounds (EDCs)) in pol-luted waterwastewater has rendered existing conventionalwaterwastewater treatment plants ineffective to meet theenvironmental standards The discharge of these compoundsinto the aquatic environment has affected all living organ-isms The traditional materials and treatment technologieslike activated carbon oxidation activated sludge nanofil-tration (NF) and reverse osmosis (RO) membranes are noteffective to treat complex and complicated polluted waterscomprising pharmaceuticals personal care products surfac-tants various industrial additives and numerous chemicalspurported The conventional water treatment processes arenot able to address adequately the removal of awide spectrumof toxic chemicals and pathogenic microorganisms in rawwater

This is the right time to address water problems sinceaquifers around the world are depleting due to multiplefactors such as saltwater intrusion and contamination fromsurface waters Using better purification technologies canreduce problems of water shortages health energy andclimate change A considerable saving of potable water canbe achieved through reuse of wastewater which in turnrequires the development materials and methods which areefficient cost-effective and reliable Although dilution ofcomplex wastewater effluents can help decreasing the loadof micropollutants downstream [29 30] however muchof them pass through conventional water treatment dueto occurrence of these substances in micro- or even innanograms per liter

Biological treatment systems such as activated sludgeand biological trickling filters are unable to remove a widerange of emerging contaminants and most of these com-pounds remain soluble in the effluent [31ndash33] Physicochem-ical treatments such as coagulation flocculation or limesoftening proved to be ineffective for removing differentEDCs and pharmaceutical compounds in various studies[34ndash36] Chlorination though providing residual protectionagainst regrowth of bacteria and pathogens [37 38] results inundesirable tastes and odors [39] in addition to the formingof different disinfection by-products (DBPs) in portabledrinking water [40ndash43] Ozonation has been considered to bea less attractive alternative due to expensive costs and shortlifetime Both ultraviolet (UV) photolysis and ion exchangethough being advanced type of treatments are not feasiblealternatives for micropollutants removal [44]

Membrane processes like microfiltration ultrafiltrationNF and RO which are pressure-driven filtration processes

are considered as some new highly effective processes[44ndash49] These are considered as alternative methods ofremoving huge amounts of organic micropollutants [50ndash52] Waterwastewater treatment by membrane techniquesis cost-effective and technically feasible and can be betteralternatives for the traditional treatment systems since theirhigh efficiency in removal of pollutants meets the highenvironmental standards [53] NF and RO have proved to bequite effective filtration technologies for removal of microp-ollutants [54 55] RO is relatively more effective than NF buthigher energy consumption in RO makes it less attractivethan NF where removal of pollutants is caused by differentmechanisms including convection diffusion (sieving) andcharge effects [56] Although NF based membrane processesare quite effective in removing huge loads of micropollutants[57] advancedmaterials and treatmentmethods are requiredto treat newly emerging micropollutants

Since the water industry is required to produce drinkingwater of high quality there is a clear need for the devel-opment of cost-effective and stable materials and methodsto address the challenges of providing the fresh water inadequate amounts There are inventions of new treatmentmethods however they need to be stable economical andmore effective as compared with the already existing tech-niques For this traditional treatment technologies have tobe modernized that is updated or modified or replacedby developing materials and methods which are efficientcost-effective and reliable This is particularly important toachieve a considerable potable water savings through reuse ofwastewater in addition to tackling the day-by-day worseningquality of drinking water

Nanotechnology has been considered effective in solvingwater problems related to quality and quantity [58] Nanoma-terials (eg carbon nanotubes (CNTs) and dendrimers) arecontributing to the development of more efficient treatmentprocesses among the advanced water systems [59] Thereare many aspects of nanotechnology to address the multipleproblems of water quality in order to ensure the environmen-tal stabilityThis study provides a unique perspective on basicresearch of nanotechnology for waterwastewater treatmentand reuse by focusing on challenges of future research

The paper has three main sections following the intro-duction which briefly discusses the traditional and currentpractices in waterwastewater treatment Section 2 describesmainly the properties and types of nanomaterials and theirimportance in waterwastewater treatment Section 3 dis-cusses different types of nanomaterials focusing on mem-branes for treating a variety of pollutants inwaterwastewaterThe application of nanomaterials is reviewed based on theirfunctions in unit operation processes Section 4 providesa summary and outlook in the form of conclusions andrecommendations for their full-scale application

2 Nanotechnology forWaterWastewater Purification

There are rising demands of clean water throughout theworld as freshwater sourcesresources are depleting due to

Advances in Materials Science and Engineering 3

prolonged droughts increasing population climate changesthreats and strict water quality standards [60 61] Masses indeveloping countries are using unconventional water sources(eg stormwater contaminated fresh water brackish water)due to limited and depleting freshwater suppliesThe existingwater treatment systems distribution systems and disposablehabits coupled with huge centralized schemes are no moresustainableThe current researches do not adequately addressthe practices that guarantee the availability of water for allusers in accordancewith the stringentwater quality standards[62]

Several commercial and noncommercial technologicaldevelopments are employed on daily basis but nanotech-nology has proved to be one of the advanced ways forwaterwaste water treatment Developments in nanoscaleresearch havemade it possible to invent economically feasibleand environmentally stable treatment technologies for effec-tively treating waterwastewater meeting the ever increasingwater quality standards Advances in nanotechnology haveprovided the opportunities to meet the fresh water demandsof the future generations It is suggested that nanotechnologycan adequately address many of the water quality issues byusing different types of nanoparticles andor nanofibers [63]Nanotechnology uses materials of sizes smaller than 100 nmin at least one dimension (Figure 1) meaning at the level ofatoms andmolecules as comparedwith other disciplines suchas chemistry engineering and materials science [64 65]

At this scale materials possess novel and significantlychanged physical chemical and biological properties mainlydue to their structure higher surface area-to-volume ratiooffering treatment and remediation sensing and detectionand pollution prevention [66 67] These unique propertiesof nanomaterials for example high reactivity and strongsorption are explored for application in waterwastewatertreatment based on their functions in unit operations ashighlighted in Table 1 [68]

Nanoparticles can penetrate deeper and thus can treatwaterwastewater which is generally not possible by con-ventional technologies [69] The higher surface area-to-volume ratio of nanomaterials enhances the reactivity withenvironmental contaminants

In the context of treatment and remediation nanotech-nology has the potential to provide both water quality andquantity in the long run through the use of for examplemembranes enabling water reuse desalination In additionit yields low-cost and real-time measurements through thedevelopment of continuous monitoring devices [70 71]Nanoparticles having high absorption interaction and reac-tion capabilities can behave as colloid by mixing mixed withaqueous suspensions and they can also display quantum sizeeffects [72ndash76] Energy conservation leading to cost savings ispossible due to their small sizes however overall usage costof the technology should be compared with other techniquesin the market [77] Figure 2 depicts some of the differenttypes of nanomaterials that can be used in waterwastewatertreatment [78ndash80]

Nanomaterials have effectively contributed to the devel-opment of more efficient and cost-effective water filtrationprocesses sincemembrane technology is considered as one of

the advanced waterwastewater treatment processes [81ndash91]Nanoparticles have been frequently used in the manufactur-ing ofmembranes allowing permeability control and fouling-resistance in various structures and relevant functionalities[92 93] Both polymeric and inorganic membranes aremanufactured by either assembling nanoparticles into porousmembranes or blending process [94ndash96] The examples ofnanomaterials used in this formation include for examplemetal oxide nanoparticles like TiO

2 CNTs have resulted in

desired outputs of improved permeability inactivation ofbacteria and so forth [97 98]

Finally nanofibrous media have also been used toimprove the filtration systems due to their high permeabilityand small pore size properties [99] They are synthesized bya new and efficient fabrication process namely electrospin-ning and may exhibit different properties depending on theselected polymers [100] In short the development of dif-ferent nanomaterials like nanosorbents nanocatalysts zeo-lites dendrimers and nanostructured catalytic membraneshas made it possible to disinfect disease causing microbesremoving toxic metals and organic and inorganic solutesfrom waterwastewater An attempt is made to highlightthe factors that may influence the efficiency of the removalprocesses based on the available literature in the followingsection

3 Pollutants Removal UsingDifferent Nanomaterials

31 Disinfection Biological contaminants can be classi-fied into three categories namely microorganisms naturalorganic matter (NOM) and biological toxins Microbial con-taminants include human pathogens and free livingmicrobes[101ndash105] The removal of cyanobacterial toxins is an issuein conventional water treatment systems [106 107] Manyadsorbents including activated carbon have reasonably goodremoval efficiencies and again a number of factors influencethe removal process [108ndash111]

Contamination from bacteria protozoans and viruses ispossible in both ground and surface water The toxicity ofthe standard chlorine chemical disinfection in addition tothe carcinogenic and very harmful by-products formationis already mentioned Chlorine dioxide is expensive andresults in the production of hazardous substances like chloriteand chlorate in manufacturing process Ozone on the otherhand has no residual effects but produces unknown organicreaction products For UV disinfection longer exposure timeis required for effectiveness and also there is no residualeffect Despite advances in disinfection technology outbreaksfrom waterborne infections are still occurring So advanceddisinfection technologies must at least eliminate the emerg-ing pathogens in addition to their suitability for large-scaleadoption There are many different types of nanomaterialssuch as Ag titanium and zinc capable of disinfecting water-borne disease-causingmicrobes Due to their charge capacitythey possess antibacterial properties TiO

2photocatalysts

and metallic and metal-oxide nanoparticles are among themost promising nanomaterials with antimicrobial properties


Water Glucose Antibody Virus Bacterium Cancer cell A period Tennis ball

10minus1 1 10 10

310

210

410

510

610

710

8

NanodevicesNanoporesDendrimersNanotubesQuantum dotsNanoshells

(nm)

Figure 1 A size comparison of nanoparticle with other larger-sized materials

Table 1 Examples of potential applications of nanotechnology in waterwastewater treatment

Applications Examples of nanomaterials Some of novel properties

Adsorption CNTsnanoscale metal oxide and nanofibersHigh specific surface area and assessable adsorption sitesselective and more adsorption sites short intraparticle diffusiondistance tunable surface chemistry easy reuse and so forth

Disinfection Nanosilvertitanium dioxide (AgTiO2) and CNTs Strong antimicrobial activity low toxicity and cost highchemical stability ease of use and so forth

Photocatalysis Nano-TiO2 and Fullerene derivatives Photocatalytic activity in solar spectrum low human toxicityhigh stability and selectivity low cost and so forth

Membranes Nano-AgTiO2ZeolitesMagnetite and CNTsStrong antimicrobial activity hydrophilicity low toxicity tohumans high mechanical and chemical stability highpermeability and selectivity photocatalytic activity and so forth

The efficacy of metal ions in water disinfection has beenhighlighted by many researchers [112] This part of the papercovers the application of these antimicrobial nanomaterialsfor water disinfection

311 Silver Nanoparticles Silver is the most widely usedmaterial due to its low toxicity and microbial inactivation inwater [113ndash116] with well-reported antibacterial mechanism[117 118] Silver nanoparticles are derived from its salts likesilver nitrate and silver chloride and their effectiveness asbiocides is documented in the literature [119ndash123] Thoughthe antibacterial effect is size dependent [124] smaller Agnanoparticles (8 nm)weremost effective while larger particlesize (11ndash23 nm) results in lower bactericidal activity [125]Also truncated triangular silver nanoplates exhibited bet-ter antibacterial effects than the spherical and rod-shapednanoparticles indicating their shape dependency [126] Themechanisms involved during the bactericidal effects of Agnanoparticles include for example the formation of freeradicals damaging the bacterial membranes [127 128] inter-actions with DNA adhesion to cell surface altering themembrane properties and enzyme damage [122 129 130]

Immobilized nanoparticles have gained importance dueto high antimicrobial activity [131] Embedded Ag nanopar-ticles have been reported as very effective against bothGram-positive and Gram-negative bacteria [63] In a study

the cellulose acetate fibers embedded with Ag nanoparti-cles by direct electrospinning method [132] were showneffective against both types of bacteria Ag nanoparticlesare also incorporated into different types of polymers forthe production of antimicrobial nanofibers and nanocom-posites [133ndash135] Poly (120576-caprolactone-) based polyurethanenanofiber mats containing Ag nanoparticles were preparedas antimicrobial nanofilters in a study [136] Differenttypes of nanofibers containing Ag nanoparticles are pre-pared for antimicrobial application and exhibited very goodantimicrobial properties [137ndash139] Water filters prepared bypolyurethanersquos foam coated with Ag nanofibers have showngood antibacterial properties against Escherichia coli (E coli)[112]

There are other examples of low-cost potable microfiltersprepared by incorporating Ag nanoparticles that can beused in remote areas in developing countries [140] Agnanoparticles also find their applications in water filtrationmembranes for example in polysulfonemembranes [141] forbiofouling reduction and have proved effective against varietyof bacteria and viruses [142ndash148] These Ag nanoparticlesladen membranes had good antimicrobial activities againstE coli Pseudomonas and so forth [149 150]

Finally Ag nanocatalyst alone and incorporate withcarbon covered in alumina has been demonstrated as efficientfor degradation of microbial contaminants in water [151]


(a) TEM image of TiO2 nanocrystals (b) SEM images of aligned CNTs

(c) AFM image of Zinc oxide (ZnO) nanoparticles (d) Optical microscope image of Sn-doped ZnOnanobelts

Figure 2 Examples of different types of nanomaterials including particles crystals tube and belts

Although Ag nanoparticles have been used efficiently forinactivating bacteria and viruses as well as reducing mem-brane biofouling their long-term efficacy against membranebiofouling has not been reported mainly due to loss of silverions with time [152 153] So further work to reduce this lossof silver ions is required for long-term control of membranebiofouling Alternatively doping of Ag nanoparticles withother metallic nanoparticles or its composites with metal-oxide nanoparticles can solve the issue and this could alsolead to the parallel removal of inorganicorganic compoundsfrom waterwastewater

312 TiO2Nanoparticles TiO

2nanoparticles are among the

emerging andmost promising photocatalysts forwater purifi-cation [154 155] The basic mechanism of a semiconductor-based photocatalysts like low-cost TiO

2having good pho-

toactivity and nontoxicity [156] involves the production ofhighly reactive oxidants such as OH radicals for disin-fection of microorganisms bacteria fungi algae virusesand so forth [157ndash165] TiO

2 after 8 hours of simulated

solar exposure has been reported to reduce the viability ofseveral waterborne pathogens such as protozoa fungi E coli

and Pseudomonas aeruginosa [166] A complete inactivationof fecal coliforms under sunlight is reported in a studyexpressing the photocatalytic disinfection efficiency of TiO

2

[167]The limited photocatalytic capability of TiO

2 that is only

under UV light has improved drastically by extending itsoptical absorbance to the visible-light region [168 169] Thiswas achieved by doping transition metals [170] and anionicnonmetals such as nitrogen [171ndash180] carbon [181ndash187] sul-fur [188ndash190] or fluorine [191] into TiO

2 Recently Ag doping

of TiO2has resulted in improved bacterial inactivation either

by complete removal or decreased time of E coli inactivationthereby enhancing disinfection under UV wavelengths andsolar radiations [192ndash197]

As highlighted the synthesis of visible-light-activatedTiO2nanoparticles has attracted considerable interest [198]

and TiO2nanoparticles and nanocrystallines irradiated with

UV-visible light exhibited strong bactericidal activity againstE coli [199ndash202] Metal-doped TiO

2nanoparticles sulfur

and iron in couple of studies have shown strong antibacterialeffects against E coli [203 204] TiO

2was furthermodified by

nanoparticles of transition metal oxides and nanostructured


TiO2photocatalysts showed great potential for water dis-

infection For example metal-ion-modified nitrogen-dopedTiO2nanoparticle photocatalysts (palladium (Pd) in a study)

have shown enhanced disinfection efficiency against E coli(Gram-negative bacterium) Pseudomonas aeruginosa andBacillus subtilis spores due to photocatalytic oxidation undervisible-light illumination [205 206]

Nitrogen-dopedTiO2nanoparticles catalysts have proved

their efficiency for degradation of microbial contaminantsin water [151] Nanostructured TiO

2films and membranes

are capable of disinfecting microorganisms in addition to thedecomposition of organic pollutants under UV and visible-light irradiation [207] Due to its stability in water TiO

2

can be incorporated in thin films or membrane filters forwater filtration [208 209] TiO

2nanorods and nanofilms

exhibited a higher photocatalytic activity than commercialTiO2nanoparticles and TiO

2thin films respectively for

the photocatalytic inactivation of E coli [191 210 211] Theinactivationmechanism of E coliwhen using TiO

2thin films

was also investigated by many researchers [212 213] In astudy TiO

2nanocomposites with multiwalled CNTs showed

the complete inactivation of bacterial endospores (Bacilluscereus) compared to commercial TiO

2nanoparticles [214]

Immobilized TiO2nanoparticle films successfully inactivated

E coli K12 in surface and distilled water [215] TiO2nanopar-

ticles incorporated into an isotactic polypropylene polymericmatrix showed higher biocidal activity against Enterococcusfaecalis and Pseudomonas aeruginosa [216]

The detailed review has demonstrated the antibacterialefficiency of TiO

2nanoparticles but the actual underlying

mechanisms are not well defined especially under visiblelight In addition composites of TiO

2nanoparticles by dop-

ing with other metallic nanoparticles have also shown theireffectiveness but the applications of using TiO

2nanofibers

and thin films need to be investigated for the effective removalof both inorganicorganic compounds in addition to thedisinfection

313 CNTs andOthers CNTshave proved to be very effectivein removing bacterial pathogens CNTs (one of nanosor-bents) which have been used for removal of biologicalimpurities have received special attention for their excellentcapabilities of removing biological contaminants from water[63] CNTs possess antimicrobial characteristics against awide range of microorganisms including bacteria such as Ecoli and Salmonella [217ndash222] and viruses [223 224] Theadsorption of cyanobacterial toxins on CNTs is also higherwhen compared with carbon-based adsorbents mainly due tolarge specific surface area external diameter of CNTs largecomposition of mesoporous volume and so forth [225ndash228]

Researchers have attributed the antimicrobial effects ofCNTs to their unique physical cytotoxic and surface func-tionalizing properties [229] their fibrous shape [230 231]the size and length of the tubes and number of layers(single- or multiwalled) [155 232]Themechanisms of killingbacteria by CNTs are also due to the production of oxidativestress disturbances to cell membrane and so forth [233]Although single-walled CNTs are more detrimental against

microorganisms thanmultiwalledCNTs [234] dispersivity ofCNTs is amore important parameter than length [235] Manyresearchers observed an extremely high adsorption rate ofbacteria by single-walled CNTs in addition to their highsorption capacities by many researchers [236ndash244]

Filtration membranes containing radially aligned CNTsare very effective in removing both bacteria and viruses invery short time due to size exclusion and depth filtration[245ndash247] and thus enable such filters to be used as cost-effective and point-of-use water disinfection devices CNTscan also reduce membrane biofouling and a nanocompositemembrane of single-walled CNTs and polyvinyl-N-carbazoleshowed high inactivation of bacteria upon direct contact in astudy [248] Another example of controlling the biofoulingin thin film nanocomposite membranes is the single-walledCNTs covalently bonded to thin film composite membranesurface which have exhibited moderate antibacterial proper-ties [249]

Among the other nanomaterials for microbial disinfec-tion bifunctional ferrous oxide (Fe

3O4) Ag and Fe

3O4

TiO2nanoparticles were employed successfully against

pathogenic bacteria including E coli Staphylococcus epider-midis and Bacillus subtilis thus covering both Gram-positiveand Gram-negative bacteria as well as spores [250 251]Magnesium oxide nanoparticles were also used effectivelyas biocides against both Gram-positive and Gram-negativebacteria and bacterial spores [252 253]Nanotungsten oxideand palladium-incorporated ZnO nanoparticles have showngood antibacterial properties at removal of E coli fromwater [254 255] Nitrogen-doped ZnO and Zirconium oxidenanoparticles also have proved good antibacterial nanostruc-tured materials [151 256]

32 Desalination Desalination is considered an importantalternative for obtaining fresh water source Though expen-sive membrane based desalination processes cover most ofthe desalination capability out of which only RO accountsfor 41 [257] Parameters that control the desalination costinclude maximizing the flux of water through membrane tominimize the fouling Recent developments in membranetechnology have resulted in energy efficiency in RO plants[258] NF has also been evaluated for desalinating seawater[259]

Nanomaterials are very useful in developing more effi-cient and cheaper nanostructured and reactive membranesfor waterwastewater treatment and desalination such asCNT filters [260] Nanomaterials offer opportunities to con-trol the cost of desalination and increase its energy efficiencyand among these are CNTs [261 262] zeolites [263 264]and graphene [265ndash267]The controlled synthesis of both thelength and diameters of CNTs has enabled them to be used inRO membranes to achieve high water fluxes [268ndash270]

Thin film nanocomposite membranes containing Ag andTiO2nanoparticles exhibited good salt rejection [150 271]

Membrane permeability and salt rejection are shown to beeffected by the number of coatings in TiO

2Al2O3(alu-

miniumoxide) composite ceramicmembranes coated by iron


oxide nanoparticles (Fe2O3) [272 273] A high sodium chlo-

ride rejection was obtained by using alumina ceramic mem-branes fabricated with silica nanoparticles [274] Zeolite-based membranes for RO have exhibited high flux withexcellent ion rejection characteristics [275 276] Studies alsohave indicated the potential of graphene membranes forwater desalination with higher fluxes than polymeric ROmembranes [277]

Other nanostructures such as lyotropic liquid crystalsand aquaporins also have exhibited high flux and selectivewater transportation [278ndash280] Zeolite-polyamide thin filmnanocomposite membranes offered new ways of designingNF and RO membranes with increased water permeabilityand high salt rejection [275 281] The use of nanozeolitesin thin film nanocomposite membranes has resulted inenhanced permeability and salt rejection [282 283]

By grafting functional groups such as carboxyl at open-ing of CNTs membranes have better selective rejection ofsome components but this has resulted in reduced permeabil-ity rendering CNTs incapable for desalination [281 284 285]Hinds concluded a uniformCNTdiameter of less than 08 nmfor high salt rejection [286] Nanocomposite membranesmay serve as ideal membranes for desalination but a basicunderstanding of transport mechanism along with properpore size selection by keeping the uniformity is required foreconomically feasible and commercially acceptable desalina-tion membranes The effects of real seawater feed on the effi-ciency of different nanomaterials need to be investigated interms of long-term operation andmaintenance of membraneperformance

33 Removal of Heavy Metals and Ions Different types ofnanomaterials have been introduced for removal of heavymetals from waterwastewater such as nanosorbents includ-ingCNTs zeolites and dendrimers and they have exceptionaladsorption properties [63] The ability of CNTs to adsorbheavy metals is reviewed by many researchers [287] such asCd2+ [288] Cr3+ [289] Pb2+ [290] and Zn2+ [291] and met-alloids such as arsenic (As) compounds [292] Compositesof CNTs with Fe and cerium oxide (CeO

2) have also been

reported to remove heavymetal ions in few studies [293ndash295]Cerium oxide nanoparticles supported on CNTs are usedeffectively to adsorb arsenic [289] Fast adsorption kinetics ofCNTs is mainly due to the highly accessible adsorption sitesand the short intraparticle diffusion distance [287]

Metal based nanomaterials proved to be better in remov-ing heavy metals than activated carbon [296] for exampleadsorption of arsenic by using TiO

2nanoparticles and nano-

sized magnetite [297 298] The utilization of photocatalystssuch as TiO

2nanoparticles has been investigated in detail

to reduce toxic metal ions in water [299] In a study theeffectiveness of nanocrystalline TiO

2in removing different

forms of arsenic is elaborated and it has shown to be moreeffective photocatalyst than commercially available TiO

2

nanoparticles with a maximum removal efficiency of arsenicat about neutral pH value [300] A nanocomposite of TiO

2

nanoparticles anchored on graphene sheet was also usedto reduce Cr(VI) to Cr(III) in sunlight [301] Similar Cr

treatment was carried out by using palladium nanoparticlesin another study [302]

The capability of removing heavy metals like As is alsoinvestigated by using iron oxide nanomaterials (Fe

2O3and

Fe3O4) as cost-effective adsorbents by many researchers

[303ndash305] Arsenic removal was also investigated by usinghigh specific surface area of Fe

3O4nanocrystals [306]

Polymer-grafted Fe2O3nanocomposite was effectively used

to remove divalent heavy metal ions for copper nickel andcobalt over a pH range of 3 to 7 [307]

Bisphosphonate-modified magnetite nanoparticles werealso used to remove the radioactive metal toxins uraniumdioxide (UO

2

2+) with high efficiency from water [308] Stud-ies have shown that zero-valent iron or iron nanoparticles(nZVI or Fe0) are very effective for the transformation ofheavymetal ions such asAs(III) As(V) Pb(II) Cu(II) Ni(II)andCr(VI) [309ndash313] Reduction ofCr(VI) toCr(III)was alsodone by using nZVI and bimetallic nZVI nanoparticles in astudy [314]

Novel self-assembled 3D flower-like iron oxide nanos-tructures were also used to successfully adsorb both As(V)and Cr(VI) [315] The 3D nanostructures of CeO

2are

used as good adsorbents for both As and Cr [316] Theefficiency of NaP1 zeolites was evaluated for removal ofheavy metals (Cr(III) Ni(II) Zn(II) Cu(II) and Cd(II))from wastewater [317 318] Dendritic polymers were alsoused for treatment of toxic metal ions [319] The applicabilityof self-assembled monolayers on mesoporous supports forremoving toxic metal ions novel was also evaluated by manyresearchers [320ndash322] Biopolymers have been used for heavymetal remediation from aqueous wastes [323 324] Chitosannanoparticles for the sorption of Pb(II) were also used in onestudy [325]

NF is reviewed for the removal of cations and arsenicfrom groundsurface waters [326] and it has been shownvery effective to remove uranium (VI) from sea water [327]Novel nanofilter membranes prepared by assembling positivepoly (allylamine hydrochloride) and negative poly (styrenesulfonate) onto porous alumina exhibited a high retention ofCa2+ and Mg2+ [85] The incorporation of iron (hydr)oxidenanoparticles into porous carbon materials has made it pos-sible to remove both inorganics and organics thus enablingsuch filters to be used as point-of-use applications [328 329]A dendrimer-UF system was used for the removal of Cu2+and the complete removal from water was obtained [330]Finally there are commercial products for efficient removalof arsenic and these include iron oxide nanoparticles andpolymers and nanocrystalline titanium dioxide medium inthe form of beads [331 332]

34 Removal of Organic Contaminants NOM constitutes adiverse group of hydrophobic (humic and fulvic acids) andhydrophilic organic compounds and it contributes signifi-cantly towards water contamination [333ndash339] A variety ofcarbon-based adsorbents have been used for the removal ofNOM from raw water and several factors affect this sorptionof NOM [340ndash343]


341 CNTs Different types of nanomaterial like nanosor-bents such as CNTs polymeric materials (eg dendrimers)and zeolites have exceptional adsorption properties and areapplied for removal of organics from waterwastewater [63]CNTs have received special attention due to their exceptionalwater treatment capabilities and adsorption of organics onCNTs is widely studied and extensively reviewed [287] Theremoval of NOM by CNTs is higher when compared withcarbon-based adsorbents mainly due to large surface areasand other factors [344 345] CNTs are also effective toremove polycyclic aromatic organic compounds [346ndash348]and atrazine [345]

Nanoporous activated carbon fibers prepared by elec-trospinning of CNTs showed much higher organic sorptionequilibriumconstants for benzene toluene xylene and ethyl-benzene than granular activated carbon [349] The sorptionof 12-dichlorobenzene by CNTs has been shown as effectivein one study [350] Compared with activated carbon bothsingle- and multiwalled CNTs displayed higher adsorptioncapacities for trihalomethanes [293 351] Multiwalled CNTshave been used as sorbents for chlorophenols herbicidesDDTs and so forth [352ndash355] Finally novel polymers withfunctionalized CNTs showed effective removal of organicpollutants from water [295]

342 TiO2Nanoparticles Metal oxide nanomaterials such as

TiO2in addition to CeO

2have also been used as catalysts

for fast and comparatively complete degradation of organicpollutants in ozonation processes [356 357] Photocatalystslike TiO

2nanoparticles are used effectively for the treatment

of water contaminated with organic pollutants like polychlo-rinated biphenyls (PCBs) benzenes and chlorinated alkanes[299] Removal of total organic carbon from wastewater wasenhanced by the addition of TiO

2nanoparticles in a study

[358] TiO2nanoparticles were also used in a ldquofalling filmrdquo

reactor for the degradation of microcystins in water [159]Multiwalled CNTs functionalized with Fe nanoparticles havebeen proved effective sorbents for aromatic compounds likebenzene and toluene [359]

Decomposition of organic compounds can be enhancedby noble metal doping into TiO

2due to enhanced hydroxyl

radical production and so forth [360ndash362] For examplethe doping Si into TiO

2nanoparticles was effective to

improve its efficiency due to the increase in surface areaand crystallinity [363 364] TiO

2nanocrystals modified

with noble metal deposits and so forth were used for thedegradation of methylene blue in the visible-light range [198365 366] Nitrogen- and Fe(III-) doped TiO

2nanoparticles

were better in degrading azo dyes and phenol respectivelythan commercially available TiO

2nanoparticles [367 368]

TiO2nanoparticles deposited onto porous Al

2O3were used

effectively for the removal of TOC in a study [369] TiO2

nanocomposites with mesoporous silica were also used forthe treatment of aromatic pollutants [370ndash373] A compositeof nanosized SO

4

2minusTiO2was used for the degradation of 4-

nitrophenol in one study [374] TiO2nanotubes have been

used effectively to degrade toluene better than bulk structuralmaterials [375] and were found to be more efficient than

TiO2nanoparticles for degrading organic compounds [376]

A commercial product (Purifics Photo-Cat system) has beenshown highly efficient at removing organics [377ndash379]

343 Zero-Valent Iron Nanocatalysts including semicon-ductor materials zero-valence metal and bimetallic nano-particles have been used for degradation of environmentalcontaminants such as PCBs pesticides and azo dyes dueto their higher surface area and shape dependent properties[380] Magnetic nanosorbents also have proved effective inorganic contaminants removal [381] Iron oxide nanomate-rials have shown better removal capabilities of organic pollu-tants than bulkmaterials [303 382 383] Fe

2O3nanoparticles

have also been used for the removal of colored humic acidsfrom wastewater [384] Chlorinated organic compounds andPCBs have been transformed successfully using nZVI [385ndash387] as well as inorganic ions such as nitrate and perchlorate[388 389]

Particles of nZVI have been proved effective in degrada-tion of toxic chlorinated organic compounds for example221015840-dichlorobiphenyl in a few remediation studies [390 391]The stabilized nZVI particles could also be an effectiveway for in situ remediation of groundwater or industrialeffluents [392] The nZVI and bimetallic nZVI have emergedas effective redox media for reducing a variety of organicpollutants such as PCBs pesticides organic dyes chlorinatedalkanes and alkenes and inorganic anions (eg nitrates)in waterwastewater due to larger surface areas and reac-tivity [393 394] Bimetallic Ni0Fe0 and Pd0Fe0 nanopar-ticles were more effective than commercial microscale Fefor reductive dehalogenation of chlorinated organics andbrominated methanes hydrodechlorination of chlorinatedaliphatics chlorinated aromatics and PCBs as reported bymany researchers [395ndash402]

344 Other Nanomaterials In a study nanostructured ZnOsemiconductor films were used for degradation of organiccontaminants (4-chlorocatechol) [403] The nanocatalyst ofAg and amidoxime fibers was used efficiently for degradationof organic dyes [404] A bimetallic nanocomposite of Pd-Cu120574-alumina was used for the reduction of nitrate in onestudy [405] Traces of halogenated organic compounds werebiodegraded using hydrogen and the Pd based nanoparticles[301 406] Pd nanoparticles and bimetallic PdAu (gold)nanoparticles were used effectively for hydrodechlorinationof trichloroethylene (TCE) [407 408] Mineralization oforganic dyes was accelerated in one study by using filmsof manganese oxide (MnO

2) nanoparticles and hydrogen

peroxide [409] Similarly MnO2hierarchical hollow nanos-

tructures were used for the removal of organic pollutantin waste water [410] The immobilized nanoparticles ofmetallo-porphyrinogens have also been successfully used forthe reductive dehalogenation of chlorinated organic com-pounds (TCE and carbon tetrachloride) [411] The applica-bility of self-assembled monolayers on mesoporous supportsfor removing anions and radionuclides was also evalu-ated by many researchers [412 413] Molecularly imprintednanospheres were used for the removal of micropollutants


from hospital waste water [414] Finally single-enzymenanoparticles could be used for decontaminating a broadrange of organic contaminants as highlighted in one study[415]

345 Membranes The immobilization of metallic nanopar-ticles in membrane has also been proved effective for degra-dation and dechlorination of toxic contaminants [416] Inor-ganic membranes containing nano-TiO

2or modified nano-

TiO2have been used effectively for reductive degradation

of contaminants particularly chlorinated compounds [417418]The use of TiO

2immobilized on a polyethylene support

and a TiO2slurry in combinationwith polymericmembranes

has proved very effective in degrading 12-dichlorobenzeneand pharmaceuticals respectively [419 420]

Polyethersulfone composite membranes with nano-TiO2

as additive showed higher fluxes and enhanced antifoulingproperties [421ndash423] Ceramic compositemembranemade ofTiO2nanoparticles inside a tubular Al

2O3substrate showed

improved water quality and flux compared to Al2O3mem-

branes [424] By doping TiO2nanoparticles to the Al

2O3

membrane it was possible to control the membrane foulingby decreased adsorption of oil droplets to membrane surfacein the treatment of oily wastewater [425] Nanostructuredcomposite of TiO

2and Fe

2O3incorporated into ultrafiltra-

tion membranes successfully reduced the fouling burden andimproved the permeate flux [369]

Cellulose acetate membrane laden with nZVI was foundeffective in dechlorination of TCE [426] A reactive mem-brane of bimetallic nZVI and Pt0 nanoparticles was foundto be very effective at reducing TCE [427] Bimetallic FeNiand FePd nanoparticles incorporated in nZVI as polymerndashinorganic porous composite membranes have been suc-cessfully used for the reductive degradation of halogenatedorganic solvents [428ndash430] Polyvinylidene fluoride film con-taining Pd and PdFe was used effectively for dechlorinationof PCBrsquos in one study [431] leading to the development ofa membrane reactor for dechlorination of a wider rangeof compounds [391 432] Alumina-zirconia-titania ceramicmembrane coated with Fe

2O3nanoparticles was observed

to reduce the dissolved organic carbon better than theuncoated membrane enhancing the degradation of NOM[273 433] Finally ceramic composite membranes of TiO

2

and CNTs have resulted in enhancedmembrane permeabilityand photocatalytic activity [434ndash436]

NF is reviewed for the removal of NOM and nitratesfrom groundsurface waters [326] and it has been reportedto improve the water quality with a substantial reduction inorganic contaminants [437] Cost-effective nanostructuredand reactive membranes are fabricated using different nano-materials to develop more efficient water purification meth-ods and in a study ceramicmembrane of Al

2O3nanoparticles

alone and doped with Fe Mn and La showed selectivitytowards three different synthetic dyes [84] An improvedantifouling performance and flux increase was also observedin silica-incorporated membranes [438]

In the context of improving the UF processes for watertreatment containing organic and inorganic solutes dendritic

polymers are used as water-soluble ligands for radionuclidesand inorganic anions [439 440] Nearly complete reductionof 4-nitrophenol was seen when using a composite mem-brane composed of alumina and polymers through layer-by-layer adsorption of polyelectrolytes and citrate-stabilizedAu nanoparticles [89] Finally the addition of metal oxidenanoparticles including silica TiO

2 alumina and zeolites

to polymeric ultrafiltration membranes has helped reducingfouling [441ndash445]

4 Conclusions and Perspectives

Safe water has become a competitive resource in manyparts of the world due to increasing population prolongeddroughts climate change and so forth Nanomaterials haveunique characteristics for example large surface areas sizeshape and dimensions thatmake themparticularly attractivefor waterwastewater treatment applications such as disin-fection adsorption and membrane separations The reviewof the literature has shown that waterwastewater treatmentusing nanomaterials is a promising field for current andfuture research

Surface modifications of different nanomaterials likenanoscale TiO

2 nZVI by coupling with a second catalytic

metal can result in enhanced waterwastewater quality whenapplied for this purpose by increasing the selectivity andreactivity of the selected materials Surface modification maylead to the enhanced photocatalytic activity of the selectedcompounds due to the short lifetime of reactive oxygenspecies and increase the affinity of modified nanomateri-als towards many emerging water contaminants Bimetallicnanoparticles have also proved effective for remediation ofwater contaminantsHowever further studies are required forunderstanding the mechanism of degradation on bimetallicnanoparticles responsible for the improved efficiency For realfield applications however an improvedunderstanding of theprocessmechanism is very important for the successful appli-cations of innovative nanocomposites for waterwastewatertreatment

Electrospinning offers the way to modify the surfaceproperties of nanomaterials and different nanofibrous fil-ters have successfully been used as antifouling water fil-tration membranes They have extremely high surface-to-volume ratio and porosity are very active against water-borne pathogens less toxic with minimum health risksand provide solutions to ensure safe water It is very easyto dope functional nanomaterials to form multifunctionalmediamembrane filters with increased reactivity and selec-tivity for different contaminants Although these electrospunnanofibers are prepared by simple and cost-effective methodtheir manufacturing at industrial scale is still a challengeand it is vital to consider the subject from an engineeringaspect The use of nanofibrous composites membranes forwaterwastewater treatment is very limited and a stand-alonesystem (Figure 3) is proposed for removing all types ofcontaminants including bacteriaviruses heavy metals andions and complex organic compounds


Contaminated waterwastewater

Bacteriaviruses removal medium

Heavy metalsions removal medium

Organics removal medium

Treated water

Figure 3 Schematic of a proposed composite nanofibrousmediamembrane filters for complete removal of contaminantsfrom waterwastewater

The use of nanofibers and composite nanostructuresmembranes can help degrade a wide range of organic andinorganic contaminants in real field applications The betterunderstanding of the formation of nanocomposites mem-branes will certainly be a step towards improving the per-formance of multifunctional nanocomposites membranesThe pattern of nanoparticles within the host matrices ofmembranes and changes in the structures and propertiesof both nanomaterials and host matrices could be amongthe priority concerns in the real field applications of thenanofibrous membranes for waterwastewater treatment

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgment

This project was supported by the NSTIP strategic technolo-gies program Grant no 11-WAT1875-02 Kingdom of SaudiArabia

References

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[2] M Moore P Gould and B S Keary ldquoGlobal urbanizationand impact on healthrdquo International Journal of Hygiene andEnvironmental Health vol 206 no 4-5 pp 269ndash278 2003

[3] D M Johnson D R Hokanson Q Zhang K D Czupinskiand J Tang ldquoFeasibility of water purification technology in

rural areas of developing countriesrdquo Journal of EnvironmentalManagement vol 88 no 3 pp 416ndash427 2008

[4] M A Montgomery and M Elimelech ldquoWater and sanitationin developing countries Including health in the equationrdquoEnvironmental Science and Technology vol 41 no 1 pp 17ndash242007

[5] J Theron and T E Cloete ldquoEmerging waterborne infec-tions contributing factors agents and detection toolsrdquo CriticalReviews in Microbiology vol 28 no 1 pp 1ndash26 2002

[6] K Eshelby ldquoDying for a drinkrdquo BritishMedical Journal vol 334no 7594 pp 610ndash612 2007

[7] P Leonard S Hearty J Brennan et al ldquoAdvances in biosensorsfor detection of pathogens in food and waterrdquo Enzyme andMicrobial Technology vol 32 no 1 pp 3ndash13 2003

[8] N J Ashbolt ldquoMicrobial contamination of drinking water anddisease outcomes in developing regionsrdquo Toxicology vol 198no 1ndash3 pp 229ndash238 2004

[9] G Hutton L Haller and J Bartram Economic and HealthEffects of Increasing Coverage of Low Cost Household DrinkingWater Supply and Sanitation Interventions World Health Orga-nization 2007

[10] World Health Organization and UNICEF Progress on Sanita-tion and Drinking-Water World Health Organization GenevaSwitzerland 2013

[11] M I LrsquovovichWorld Water Resources andTheir Future Ameri-can Geophysical Union Washington DC USA 1979

[12] S L Postel G C Daily and P R Ehrlich ldquoHuman appropri-ation of renewable fresh waterrdquo Science vol 271 no 5250 pp785ndash788 1996

[13] P H Gleick P I for S in D Environment and Security and SE Institute Water in Crisis A Guide to the Worldrsquos Fresh WaterResources Oxford University Press 1993

[14] I A Shiklomanov ldquoAppraisal and assessment of world waterresourcesrdquoWater International vol 25 no 1 pp 11ndash32 2000

[15] J Rockstrom ldquoWater for food and nature in drought-pronetropics vapour shift in rain-fed agriculturerdquo PhilosophicalTransactions of the Royal Society B Biological Sciences vol 358no 1440 pp 1997ndash2009 2003

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[17] H El-Dessouky and H Ettouney ldquoTeaching desalinationmdashamultidiscipline engineering sciencerdquoHeat Transfer Engineeringvol 23 no 5 pp 1ndash3 2002

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[19] M A Shannon P W Bohn M Elimelech J G Georgiadis BJ Marıas and A M Mayes ldquoScience and technology for waterpurification in the coming decadesrdquo Nature vol 452 no 7185pp 301ndash310 2008

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[68] XQu P J J Alvarez andQ Li ldquoApplications of nanotechnologyin water and wastewater treatmentrdquoWater Research vol 47 no12 pp 3931ndash3946 2013

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[76] S J Rosenthal ldquoBar-coding biomolecules with fluorescentnanocrystalsrdquo Nature Biotechnology vol 19 no 7 pp 621ndash6222001

[77] R A Crane and T B Scott ldquoNanoscale zero-valent iron futureprospects for an emerging water treatment technologyrdquo Journalof Hazardous Materials vol 211-212 pp 112ndash125 2012

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[79] U Manzoor M Islam L Tabassam and S U Rahman ldquoQuan-tum confinement effect in ZnO nanoparticles synthesized byco-precipitate methodrdquo Physica E vol 41 no 9 pp 1669ndash16722009

[80] S Zia M Amin U Manzoor and A S Bhatti ldquoUltra-longmulticolor belts and unique morphologies of tin-doped zincoxide nanostructuresrdquo Applied Physics A Materials Science andProcessing vol 115 no 1 pp 275ndash281 2014

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[84] K A DeFriend M R Wiesner and A R Barron ldquoAluminaand aluminate ultrafiltrationmembranes derived from aluminananoparticlesrdquo Journal of Membrane Science vol 224 no 1-2pp 11ndash28 2003

[85] B W Stanton J J Harris M D Miller and M L BrueningldquoUltrathin multilayered polyelectrolyte films as nanofiltrationmembranesrdquo Langmuir vol 19 no 17 pp 7038ndash7042 2003

[86] A M Hollman and D Bhattacharyya ldquoPore assembled multi-layers of charged polypeptides in microporous membranes forion separationrdquo Langmuir vol 20 no 13 pp 5418ndash5424 2004

[87] A N Chatterjee D M Cannon Jr E N Gatimu J V SweedlerN R Aluru and P W Bohn ldquoModeling and simulation ofionic currents in three-dimensional microfluidic devices withnanofluidic interconnectsrdquo Journal of Nanoparticle Researchvol 7 no 4-5 pp 507ndash516 2005

[88] J Xu A Dozier and D Bhattacharyya ldquoSynthesis of nanoscalebimetallic particles in polyelectrolyte membrane matrix forreductive transformation of halogenated organic compoundsrdquoJournal of Nanoparticle Research vol 7 no 4-5 pp 449ndash4672005

[89] D M Dotzauer J Dai L Sun and M L Bruening ldquoCatalyticmembranes prepared using layer-by-layer adsorption of poly-electrolytemetal nanoparticle films in porous supportsrdquo NanoLetters vol 6 no 10 pp 2268ndash2272 2006

[90] M Arkas R Allabashi D Tsiourvas E-M Mattausch andR Perfler ldquoOrganicinorganic hybrid filters based on dendriticand cyclodextrin ldquonanospongesrdquo for the removal of organic


pollutants from waterrdquo Environmental Science and Technologyvol 40 no 8 pp 2771ndash2777 2006

[91] R Allabashi M Arkas G Hormann and D TsiourvasldquoRemoval of some organic pollutants in water employingceramic membranes impregnated with cross-linked silylateddendritic and cyclodextrin polymersrdquo Water Research vol 41no 2 pp 476ndash486 2007

[92] M M Cortalezzi J Rose G F Wells J-Y Bottero A RBarron andM RWiesner ldquoCeramic membranes derived fromferroxane nanoparticles a new route for the fabrication of ironoxide ultrafiltration membranesrdquo Journal of Membrane Sciencevol 227 no 1-2 pp 207ndash217 2003

[93] J-F Li Z-L Xu H Yang L-Y Yu and M Liu ldquoEffect of TiO2

nanoparticles on the surface morphology and performance ofmicroporous PES membranerdquo Applied Surface Science vol 255no 9 pp 4725ndash4732 2009

[94] A Bottino G Capannelli and A Comite ldquoPreparation andcharacterization of novel porous PVDF-ZrO2 composite mem-branesrdquo Desalination vol 146 no 1-3 pp 35ndash40 2002

[95] S H Kim S-Y Kwak B-H Sohn and T H Park ldquoDesignof TiO

2nanoparticle self-assembled aromatic polyamide thin-

film-composite (TFC) membrane as an approach to solvebiofouling problemrdquo Journal of Membrane Science vol 211 no1 pp 157ndash165 2003

[96] J-H Li Y-Y Xu L-P Zhu J-H Wang and C-H DuldquoFabrication and characterization of a novel TiO

2nanoparticle

self-assembly membrane with improved fouling resistancerdquoJournal of Membrane Science vol 326 no 2 pp 659ndash666 2009

[97] J Kim S H R Davies M J Baumann V V Tarabara and S JMasten ldquoEffect of ozone dosage and hydrodynamic conditionson the permeate flux in a hybrid ozonation-ceramic ultrafil-tration system treating natural watersrdquo Journal of MembraneScience vol 311 no 1-2 pp 165ndash172 2008

[98] S-R Chae S Wang Z D Hendren M R Wiesner Y Watan-abe and C K Gunsch ldquoEffects of fullerene nanoparticles onEscherichia coli K12 respiratory activity in aqueous suspensionand potential use for membrane biofouling controlrdquo Journal ofMembrane Science vol 329 no 1-2 pp 68ndash74 2009

[99] R S Barhate and S Ramakrishna ldquoNanofibrous filteringmediafiltration problems and solutions from tinymaterialsrdquo Journal ofMembrane Science vol 296 no 1-2 pp 1ndash8 2007

[100] A Frenot and I S Chronakis ldquoPolymer nanofibers assembledby electrospinningrdquo Current Opinion in Colloid and InterfaceScience vol 8 no 1-2 pp 64ndash75 2003

[101] I C Escobar A A Randall and J S Taylor ldquoBacterial growthin distribution systems effect of assimilable organic carbonand biodegradable dissolved organic carbonrdquo EnvironmentalScience and Technology vol 35 no 17 pp 3442ndash3447 2001

[102] I Majsterek P Sicinska M Tarczynska M Zalewski and ZWalter ldquoToxicity of microcystin from cyanobacteria growingin a source of drinking waterrdquo Comparative Biochemistry andPhysiologymdashC Toxicology and Pharmacology vol 139 no 1-3pp 175ndash179 2004

[103] D Berry C Xi and L Raskin ldquoMicrobial ecology of drinkingwater distribution systemsrdquo Current Opinion in Biotechnologyvol 17 no 3 pp 297ndash302 2006

[104] N R Dugan and D J Williams ldquoCyanobacteria passagethrough drinkingwater filters during perturbation episodes as afunction of cell morphology coagulant and initial filter loadingraterdquo Harmful Algae vol 5 no 1 pp 26ndash35 2006

[105] S Srinivasan G W Harrington I Xagoraraki and R GoelldquoFactors affecting bulk to total bacteria ratio in drinking water

distribution systemsrdquoWater Research vol 42 no 13 pp 3393ndash3404 2008

[106] W-J Huang B-L Cheng and Y-L Cheng ldquoAdsorption ofmicrocystin-LR by three types of activated carbonrdquo Journal ofHazardous Materials vol 141 no 1 pp 115ndash122 2007

[107] FAlMomaniDW Smith andMGamal El-Din ldquoDegradationof cyanobacteria toxin by advanced oxidation processesrdquo Jour-nal of Hazardous Materials vol 150 no 2 pp 238ndash249 2008

[108] P Pendleton R Schumann and S H Wong ldquoMicrocystin-LRadsorption by activated carbonrdquo Journal of Colloid and InterfaceScience vol 240 no 1 pp 1ndash8 2001

[109] D-K Lee S-C Kim I-C Cho S-J Kim and S-W KimldquoPhotocatalytic oxidation of microcystin-LR in a fluidized bedreactor having TiO

2-coated activated carbonrdquo Separation and

Purification Technology vol 34 no 1ndash3 pp 59ndash66 2004[110] H Yan A Gong H He J Zhou Y Wei and L Lv ldquoAdsorption

ofmicrocystins by carbon nanotubesrdquoChemosphere vol 62 no1 pp 142ndash148 2006

[111] H Wang L Ho D M Lewis J D Brookes and G NewcombeldquoDiscriminating and assessing adsorption and biodegradationremoval mechanisms during granular activated carbon filtra-tion of microcystin toxinsrdquo Water Research vol 41 no 18 pp4262ndash4270 2007

[112] P Jain and T Pradeep ldquoPotential of silver nanoparticle-coatedpolyurethane foam as an antibacterial water filterrdquo Biotechnol-ogy and Bioengineering vol 90 no 1 pp 59ndash63 2005

[113] J A Spadaro T J Berger S D Barranco S E Chapin and RO Becker ldquoAntibacterial effects of silver electrodes with weakdirect currentrdquo Antimicrobial agents and chemotherapy vol 6no 5 pp 637ndash642 1974

[114] G Zhao and S E Stevens Jr ldquoMultiple parameters for thecomprehensive evaluation of the susceptibility of Escherichiacoli to the silver ionrdquo BioMetals vol 11 no 1 pp 27ndash32 1998

[115] Y Inoue M Hoshino H Takahashi et al ldquoBactericidal activityof Ag-zeolitemediated by reactive oxygen species under aeratedconditionsrdquo Journal of Inorganic Biochemistry vol 92 no 1 pp37ndash42 2002

[116] V S Kumar BMNagaraja V Shashikala et al ldquoHighly efficientAgC catalyst prepared by electro-chemical deposition methodin controlling microorganisms in waterrdquo Journal of MolecularCatalysis A Chemical vol 223 no 1-2 pp 313ndash319 2004

[117] Q L Feng J Wu G Q Chen F Z Cui T N Kim and J OKim ldquoA mechanistic study of the antibacterial effect of silverions on Escherichia coli and Staphylococcus aureusrdquo Journal ofBiomedical Materials Research vol 52 no 4 pp 662ndash668 2000

[118] M Yamanaka K Hara and J Kudo ldquoBactericidal actions ofa silver ion solution on Escherichia coli studied by energy-filtering transmission electron microscopy and proteomic anal-ysisrdquoApplied and EnvironmentalMicrobiology vol 71 no 11 pp7589ndash7593 2005

[119] I Sondi and B Salopek-Sondi ldquoSilver nanoparticles as antimi-crobial agent a case study on E coli as a model for Gram-negative bacteriardquo Journal of Colloid and Interface Science vol275 no 1 pp 177ndash182 2004

[120] C Baker A Pradhan L Pakstis D J Pochan and S I ShahldquoSynthesis and antibacterial properties of silver nanoparticlesrdquoJournal of Nanoscience and Nanotechnology vol 5 no 2 pp244ndash249 2005

[121] A Panacek L Kvıtek R Prucek et al ldquoSilver colloid nanoparti-cles synthesis characterization and their antibacterial activityrdquoThe Journal of Physical Chemistry B vol 110 no 33 pp 16248ndash16253 2006


[122] J S Kim E Kuk K N Yu et al ldquoAntimicrobial effects ofsilver nanoparticlesrdquo Nanomedicine Nanotechnology Biologyand Medicine vol 3 no 1 pp 95ndash101 2007

[123] S Shrivastava T Bera A Roy G Singh P RamachandraraoandDDash ldquoCharacterization of enhanced antibacterial effectsof novel silver nanoparticlesrdquo Nanotechnology vol 18 no 22Article ID 225103 2007

[124] J R Morones J L Elechiguerra A Camacho et al ldquoThebactericidal effect of silver nanoparticlesrdquo Nanotechnology vol16 no 10 pp 2346ndash2353 2005

[125] S Makhluf R Dror Y Nitzan Y Abramovich R Jelinek andA Gedanken ldquoMicrowave-assisted synthesis of nanocrystallineMgO and its use as a bacteriociderdquo Advanced FunctionalMaterials vol 15 no 10 pp 1708ndash1715 2005

[126] S Pal Y K Tak and J M Song ldquoDoes the antibacterial activityof silver nanoparticles depend on the shape of the nanoparticleA study of the gram-negative bacterium Escherichia colirdquoApplied and EnvironmentalMicrobiology vol 73 no 6 pp 1712ndash1720 2007

[127] Z-M Xiu J Ma and P J J Alvarez ldquoDifferential effectof common ligands and molecular oxygen on antimicrobialactivity of silver nanoparticles versus silver ionsrdquoEnvironmentalScience and Technology vol 45 no 20 pp 9003ndash9008 2011

[128] Z-M Xiu Q-B Zhang H L Puppala V L Colvin and P JJ Alvarez ldquoNegligible particle-specific antibacterial activity ofsilver nanoparticlesrdquo Nano Letters vol 12 no 8 pp 4271ndash42752012

[129] S Y Liau D C Read W J Pugh J R Furr and A D RussellldquoInteraction of silver nitrate with readily identifiable groupsrelationship to the antibacterial action of silver ionsrdquo Letters inApplied Microbiology vol 25 no 4 pp 279ndash283 1997

[130] M Danilczuk A Lund J Sadlo H Yamada and J MichalikldquoConduction electron spin resonance of small silver particlesrdquoSpectrochimica ActamdashPart A Molecular and Biomolecular Spec-troscopy vol 63 no 1 pp 189ndash191 2006

[131] A Esteban-Cubillo C Pecharroman E Aguilar J Santarenand J S Moya ldquoAntibacterial activity of copper monodispersednanoparticles into sepioliterdquo Journal ofMaterials Science vol 41no 16 pp 5208ndash5212 2006

[132] W K Son J H Youk T S Lee and W H Park ldquoPreparationof antimicrobial ultrafine cellulose acetate fibers with silvernanoparticlesrdquoMacromolecular Rapid Communications vol 25no 18 pp 1632ndash1637 2004

[133] L Balogh D R Swanson D A Tomalia G L Hagnauer andA T McManus ldquoDendrimer-Silver Complexes and Nanocom-posites as Antimicrobial Agentsrdquo Nano Letters vol 1 no 1 pp18ndash21 2001

[134] Y Chen L Wang S Jiang and H Yu ldquoStudy on NovelAntibacterial Polymer Materials (I) Preparation of ZeoliteAntibacterial Agents andAntibacterial Polymer Composite andTheir Antibacterial Propertiesrdquo Journal of Polymer Materialsvol 20 no 3 pp 279ndash284 2003

[135] M Botes and T E Cloete ldquoThe potential of nanofibers andnanobiocides in water purificationrdquo Critical Reviews in Micro-biology vol 36 no 1 pp 68ndash81 2010

[136] H J Jeon J S Kim T G Kim J H Kim W-R Yu and J HYouk ldquoPreparation of poly(120576-caprolactone)-based polyure-thane nanofibers containing silver nanoparticlesrdquo Applied Sur-face Science vol 254 no 18 pp 5886ndash5890 2008

[137] N L Lala R Ramaseshan L Bojun et al ldquoFabrication ofnanofibers with antimicrobial functionality used as filters

protection against bacterial contaminantsrdquo Biotechnology andBioengineering vol 97 no 6 pp 1357ndash1365 2007

[138] C-Y Chen and C-L Chiang ldquoPreparation of cotton fibers withantibacterial silver nanoparticlesrdquoMaterials Letters vol 62 no21-22 pp 3607ndash3609 2008

[139] K Vimala K Samba Sivudu Y Murali Mohan B Sreedharand K Mohana Raju ldquoControlled silver nanoparticles synthesisin semi-hydrogel networks of poly(acrylamide) and carbohy-drates a rational methodology for antibacterial applicationrdquoCarbohydrate Polymers vol 75 no 3 pp 463ndash471 2009

[140] M Peter-Varbanets C Zurbrugg C Swartz and W PronkldquoDecentralized systems for potable water and the potential ofmembrane technologyrdquoWater Research vol 43 no 2 pp 245ndash265 2009

[141] K Zodrow L Brunet S Mahendra et al ldquoPolysulfone ultra-filtration membranes impregnated with silver nanoparticlesshow improved biofouling resistance and virus removalrdquoWaterResearch vol 43 no 3 pp 715ndash723 2009

[142] H J Lee S Y Yeo and S H Jeong ldquoAntibacterial effect ofnanosized silver colloidal solution on textile fabricsrdquo Journal ofMaterials Science vol 38 no 10 pp 2199ndash2204 2003

[143] Y Lv H Liu Z Wang et al ldquoSilver nanoparticle-decoratedporous ceramic composite for water treatmentrdquo Journal ofMembrane Science vol 331 no 1-2 pp 50ndash56 2009

[144] N Ma X Fan X Quan and Y Zhang ldquoAg-TiO2HAPAl

2O3

bioceramic composite membrane fabrication characterizationand bactericidal activityrdquo Journal of Membrane Science vol 336no 1-2 pp 109ndash117 2009

[145] N Ma X Quan Y Zhang S Chen and H Zhao ldquoIntegrationof separation and photocatalysis using an inorganic membranemodified with Si-doped TiO

2for water purificationrdquo Journal of

Membrane Science vol 335 no 1-2 pp 58ndash67 2009[146] B De Gusseme T Hennebel E Christiaens et al ldquoVirus dis-

infection in water by biogenic silver immobilized in polyvinyli-dene fluoride membranesrdquo Water Research vol 45 no 4 pp1856ndash1864 2011

[147] H Ma B S Hsiao and B Chu ldquoThin-film nanofibrouscomposite membranes containing cellulose or chitin barrierlayers fabricated by ionic liquidsrdquo Polymer vol 52 no 12 pp2594ndash2599 2011

[148] M S Mauter Y Wang K C Okemgbo C O Osuji E P Gian-nelis andM Elimelech ldquoAntifouling ultrafiltrationmembranesvia post-fabrication grafting of biocidal nanomaterialsrdquo ACSApplied Materials and Interfaces vol 3 no 8 pp 2861ndash28682011

[149] W-L Chou D-G Yu and M-C Yang ldquoThe preparationand characterization of silver-loading cellulose acetate hollowfiber membrane for water treatmentrdquo Polymers for AdvancedTechnologies vol 16 no 8 pp 600ndash607 2005

[150] S Y Lee H J Kim R Patel S J Im J H Kim and BR Min ldquoSilver nanoparticles immobilized on thin film com-posite polyamide membrane characterization nanofiltrationantifouling propertiesrdquo Polymers for Advanced Technologies vol18 no 7 pp 562ndash568 2007

[151] S Chaturvedi P N Dave and N K Shah ldquoApplications ofnano-catalyst in new erardquo Journal of Saudi Chemical Society vol16 no 3 pp 307ndash325 2012

[152] D-G YuM-Y TengW-L Chou andM-C Yang ldquoCharacter-ization and inhibitory effect of antibacterial PAN-based hollowfiber loaded with silver nitraterdquo Journal of Membrane Sciencevol 225 no 1-2 pp 115ndash123 2003


[153] J S Taurozzi H Arul V Z Bosak et al ldquoEffect of fillerincorporation route on the properties of polysulfone-silvernanocomposite membranes of different porositiesrdquo Journal ofMembrane Science vol 325 no 1 pp 58ndash68 2008

[154] A A Adesina ldquoIndustrial exploitation of photocatalysisprogress perspectives and prospectsrdquo Catalysis Surveys fromAsia vol 8 no 4 pp 265ndash273 2004

[155] Q Li S Mahendra D Y Lyon et al ldquoAntimicrobial nanoma-terials for water disinfection and microbial control potentialapplications and implicationsrdquo Water Research vol 42 no 18pp 4591ndash4602 2008

[156] K Hashimoto H Irie and A Fujishima ldquoTiO2photocatalysis

a historical overview and future prospectsrdquo Japanese Journalof Applied Physics Part 1 Regular Papers and Short Notes andReview Papers vol 44 no 12 pp 8269ndash8285 2005

[157] H Einaga S Futamura and T Ibusuki ldquoPhotocatalytic decom-position of benzene over TiO

2in a humidified airstreamrdquo

Physical Chemistry Chemical Physics vol 1 no 20 pp 4903ndash4908 1999

[158] A Fujishima T N Rao and D A Tryk ldquoTitanium dioxidephotocatalysisrdquo Journal of Photochemistry and Photobiology CPhotochemistry Reviews vol 1 no 1 pp 1ndash21 2000

[159] G S Shephard S Stockenstrom D De Villiers W J Engel-brecht and G F S Wessels ldquoDegradation of microcystintoxins in a falling film photocatalytic reactor with immobilizedtitaniumdioxide catalystrdquoWater Research vol 36 no 1 pp 140ndash146 2002

[160] J A Ibanez M I Litter and R A Pizarro ldquoPhotocatalytic bac-tericidal effect of TiO

2on Enterobacter cloacae Comparative

study with other Gram (-) bacteriardquo Journal of Photochemistryand Photobiology A Chemistry vol 157 no 1 pp 81ndash85 2003

[161] H-L Liu and T C-K Yang ldquoPhotocatalytic inactivation ofEscherichia coli and Lactobacillus helveticus by ZnO and TiO

2

activatedwith ultraviolet lightrdquoProcess Biochemistry vol 39 no4 pp 475ndash481 2003

[162] M Cho H Chung W Choi and J Yoon ldquoLinear correlationbetween inactivation of E coli and OH radical concentration inTiO2photocatalytic disinfectionrdquoWater Research vol 38 no 4

pp 1069ndash1077 2004[163] M ChoH ChungW Choi and J Yoon ldquoDifferent inactivation

behaviors of MS-2 phage and Escherichia coli in TiO2photo-

catalytic disinfectionrdquoApplied and EnvironmentalMicrobiologyvol 71 no 1 pp 270ndash275 2005

[164] P Hajkova P Spatenka J Horsky I Horska and A KolouchldquoPhotocatalytic effect of TiO

2films on viruses and bacteriardquo

Plasma Processes and Polymers vol 4 no 1 pp S397ndashS401 2007[165] L Zan W Fa T Peng and Z-K Gong ldquoPhotocatalysis effect

of nanometer TiO2and TiO

2-coated ceramic plate on Hepatitis

B virusrdquo Journal of Photochemistry and Photobiology B Biologyvol 86 no 2 pp 165ndash169 2007

[166] J Lonnen S Kilvington S C Kehoe F Al-Touati and KG McGuigan ldquoSolar and photocatalytic disinfection of proto-zoan fungal and bacterial microbes in drinking waterrdquo WaterResearch vol 39 no 5 pp 877ndash883 2005

[167] S Gelover L A Gomez K Reyes and M Teresa Leal ldquoApractical demonstration of water disinfection using TiO

2films

and sunlightrdquo Water Research vol 40 no 17 pp 3274ndash32802006

[168] M Ni M K H Leung D Y C Leung and K SumathyldquoA review and recent developments in photocatalytic water-splitting using TiO

2for hydrogen productionrdquo Renewable and

Sustainable Energy Reviews vol 11 no 3 pp 401ndash425 2007

[169] A Fujishima X Zhang and D A Tryk ldquoTiO2photocatalysis

and related surface phenomenardquo Surface Science Reports vol63 no 12 pp 515ndash582 2008

[170] V Subramanian E Wolf and P V Kamat ldquoSemiconductor-metal composite nanostructures To what extent do metalnanoparticles improve the photocatalytic activity of TiO

2

filmsrdquo Journal of Physical Chemistry B vol 105 no 46 pp11439ndash11446 2001

[171] R Asahi T Morikawa T Ohwaki K Aoki and Y Taga ldquoVisi-ble-light photocatalysis in nitrogen-doped titanium oxidesrdquoScience vol 293 no 5528 pp 269ndash271 2001

[172] C Burda Y Lou X Chen A C S Samia J Stout and J LGole ldquoEnhanced nitrogen doping in TiO

2nanoparticlesrdquoNano

Letters vol 3 no 8 pp 1049ndash1051 2003[173] H Irie Y Watanabe and K Hashimoto ldquoNitrogen-concen-

tration dependence on photocatalytic activity of TiO2-xNx

powdersrdquo Journal of Physical Chemistry B vol 107 no 23 pp5483ndash5486 2003

[174] O Diwald T L Thompson T Zubkov E G Goralski S DWalck and J T Yates Jr ldquoPhotochemical activity of nitrogen-doped rutile TiO

2(110) in visible lightrdquo Journal of Physical

Chemistry B vol 108 no 19 pp 6004ndash6008 2004[175] S Yang and L Gao ldquoNew method to prepare nitrogen-doped

titanium dioxide and its photocatalytic activities irradiated byvisible lightrdquo Journal of the American Ceramic Society vol 87no 9 pp 1803ndash1805 2004

[176] C Di Valentin G Pacchioni and A Selloni ldquoOrigin of thedifferent photoactivity of N-doped anatase and rutile TiO

2rdquo

Physical Review BmdashCondensed Matter and Materials Physicsvol 70 no 8 Article ID 85116 2004

[177] S Livraghi A Votta M C Paganini and E Giamello ldquoThenature of paramagnetic species in nitrogen doped TiO

2active

in visible light photocatalysisrdquo Chemical Communications no4 pp 498ndash500 2005

[178] S Livraghi M C Paganini E Giamello A Selloni CDi Valentin and G Pacchioni ldquoOrigin of photoactivity ofnitrogen-doped titanium dioxide under visible lightrdquo Journal ofthe American Chemical Society vol 128 no 49 pp 15666ndash156712006

[179] Y Liu J Li X Qiu and C Burda ldquoNovel TiO2nanocatalysts for

wastewater purification tapping energy from the sunrdquo WaterScience and Technology vol 54 no 8 pp 47ndash54 2006

[180] M-S Wong W-C Chu D-S Sun et al ldquoVisible-light-inducedbactericidal activity of a nitrogen-doped titanium photocatalystagainst human pathogensrdquoApplied and EnvironmentalMicrobi-ology vol 72 no 9 pp 6111ndash6116 2006

[181] S U M Khan M Al-Shahry and W B Ingler Jr ldquoEfficientphotochemical water splitting by a chemically modified n-TiO2rdquo Science vol 297 no 5590 pp 2243ndash2245 2002

[182] S Sakthivel and H Kisch ldquoDaylight photocatalysis bycarbon-modified titanium dioxiderdquo Angewandte ChemiemdashInternational Edition vol 42 no 40 pp 4908ndash4911 2003

[183] K Noworyta and J Augustynski ldquoSpectral photoresponses ofcarbon-doped TiO

2film electrodesrdquo Electrochemical and Solid-

State Letters vol 7 no 6 pp E31ndashE33 2004[184] L LinW Lin Y X Zhu et al ldquoUniform carbon-covered titania

and its photocatalytic propertyrdquo Journal of Molecular CatalysisA Chemical vol 236 no 1-2 pp 46ndash53 2005

[185] M E Rincon M E Trujillo-Camacho and A K Cuentas-Gallegos ldquoSol-gel titanium oxides sensitized by nanometric


carbon blacks comparison with the optoelectronic and photo-catalytic properties of physical mixturesrdquo Catalysis Today vol107-108 pp 606ndash611 2005

[186] HWang and J P Lewis ldquoEffects of dopant states on photoactiv-ity in carbon-doped TiO

2rdquo Journal of Physics CondensedMatter

vol 17 no 21 pp L209ndashL213 2005[187] DMitoraj A Janczyk M Strus et al ldquoVisible light inactivation

of bacteria and fungi bymodified titaniumdioxiderdquoPhotochem-ical and Photobiological Sciences vol 6 no 6 pp 642ndash648 2007

[188] T Umebayashi T Yamaki H Itoh and K Asai ldquoBand gapnarrowing of titanium dioxide by sulfur dopingrdquo AppliedPhysics Letters vol 81 no 3 pp 454ndash456 2002

[189] T Ohno T Mitsui andM Matsumura ldquoPhotocatalytic activityof S-doped TiO

2photocatalyst under visible lightrdquo Chemistry

Letters vol 32 no 4 pp 364ndash365 2003[190] T Yamamoto F Yamashita I Tanaka E Matsubara and A

Muramatsu ldquoElectronic states of sulfur doped TiO2by first

principles calculationsrdquo Materials Transactions vol 45 no 7pp 1987ndash1990 2004

[191] J C Yu J Yu W Ho Z Jiang and L Zhang ldquoEffects of F-doping on the photocatalytic activity and microstructures ofnanocrystalline TiO

2powdersrdquo Chemistry of Materials vol 14

no 9 pp 3808ndash3816 2002[192] M Sokmen F Candan and Z Sumer ldquoDisinfection of E

coli by the Ag-TiO2UV system lipidperoxidationrdquo Journal of

Photochemistry and Photobiology A Chemistry vol 143 no 2-3pp 241ndash244 2001

[193] H M Sung-Suh J R Choi H J Hah S M Koo and Y CBae ldquoComparison ofAg deposition effects on the photocatalyticactivity of nanoparticulate TiO

2under visible and UV light

irradiationrdquo Journal of Photochemistry and Photobiology AChemistry vol 163 no 1-2 pp 37ndash44 2004

[194] V Vamathevan R Amal D Beydoun G Low and S McEvoyldquoSilver metallisation of titania particles effects on photoactivityfor the oxidation of organicsrdquoChemical Engineering Journal vol98 no 1-2 pp 127ndash139 2004

[195] X Zhang M Zhou and L Lei ldquoPreparation of an Ag-TiO2photocatalyst coated on activated carbon by MOCVDrdquo

Materials Chemistry and Physics vol 91 no 1 pp 73ndash79 2005[196] K Page R G Palgrave I P Parkin M Wilson S L P Savin

and A V Chadwick ldquoTitania and silver-titania composite filmson glassmdashpotent antimicrobial coatingsrdquo Journal of MaterialsChemistry vol 17 no 1 pp 95ndash104 2007

[197] M V Liga E L Bryant V L Colvin and Q Li ldquoVirusinactivation by silver doped titanium dioxide nanoparticles fordrinking water treatmentrdquo Water Research vol 45 no 2 pp535ndash544 2011

[198] E Bae and W Choi ldquoHighly enhanced photoreductivedegradation of perchlorinated compounds on dye-sensitizedmetalTiO

2under visible lightrdquo Environmental Science and

Technology vol 37 no 1 pp 147ndash152 2003[199] J C Ireland P Klostermann EW Rice and RM Clark ldquoInac-

tivation of Escherichia coli by titanium dioxide photocatalyticoxidationrdquoApplied and EnvironmentalMicrobiology vol 59 no5 pp 1668ndash1670 1993

[200] C Wei W-Y Lin Z Zalnal et al ldquoBactericidal activity of TiO2

photocatalyst in aqueous media toward a solar-assisted waterdisinfection systemrdquo Environmental Science and Technologyvol 28 no 5 pp 934ndash938 1994

[201] M Bekbolet and C V Araz ldquoInactivation of Escherichia coli byphotocatalytic oxidationrdquo Chemosphere vol 32 no 5 pp 959ndash965 1996

[202] P-C Maness S Smolinski D M Blake Z Huang E JWolfrum and W A Jacoby ldquoBactericidal activity of photo-catalytic TiO

2reaction toward an understanding of its killing

mechanismrdquo Applied and Environmental Microbiology vol 65no 9 pp 4094ndash4098 1999

[203] J C Yu W Ho J Yu H Yip K W Po and J ZhaoldquoEfficient visible-light-induced photocatalytic disinfection onsulfur-doped nanocrystalline titaniardquo Environmental Scienceand Technology vol 39 no 4 pp 1175ndash1179 2005

[204] T A Egerton S A M Kosa and P A Christensen ldquoPhoto-electrocatalytic disinfection ofE coli suspensions by iron dopedTiO2rdquo Physical Chemistry Chemical Physics vol 8 no 3 pp

398ndash406 2006[205] P Wu R Xie and J K Shang ldquoEnhanced visible-light

photocatalytic disinfection of bacterial spores by palladium-modified nitrogen-doped titanium oxiderdquo Journal of the Amer-ican Ceramic Society vol 91 no 9 pp 2957ndash2962 2008

[206] P Wu R Xie J A Imlay and J K Shang ldquoVisible-light-induced photocatalytic inactivation of bacteria by compositephotocatalysts of palladiumoxide and nitrogen-doped titaniumoxiderdquo Applied Catalysis B Environmental vol 88 no 3-4 pp576ndash581 2009

[207] H Choi S R Al-Abed and D D Dionysiou ldquoNanostructuredtitanium oxide film- and membrane-based photocatalysis forwater treatmentrdquo in Nanotechnology Applications for CleanWater N SavageMDiallo J Duncan A Street and R SustichEds chapter 3 pp 39ndash46WilliamAndrew BostonMassUSA2009

[208] L Belhacova J Krysa J Geryk and J Jirkovsky ldquoInactivationof microorganisms in a flow-through photoreactor with animmobilized TiO

2layerrdquo Journal of Chemical Technology and

Biotechnology vol 74 no 2 pp 149ndash154 1999[209] S-Y Kwak S H Kim and S S Kim ldquoHybrid organicinorganic

reverse osmosis (RO) membrane for bactericidal anti-fouling1 Preparation and characterization of TiO

2nanoparticle self-

assembled aromatic polyamide thin-film-composite (TFC)membranerdquo Environmental Science and Technology vol 35 no11 pp 2388ndash2394 2001

[210] J Joo S G Kwon T Yu et al ldquoLarge-scale synthesis of TiO2

nanorods via nonhydrolytic sol-gel ester elimination reactionand their application to photocatalytic inactivation of E colirdquoJournal of Physical Chemistry B vol 109 no 32 pp 15297ndash153022005

[211] K-J Shieh M Li Y-H Lee S-D Sheu Y-T Liu and Y-CWang ldquoAntibacterial performance of photocatalyst thin filmfabricated by defection effect in visible lightrdquo NanomedicineNanotechnology Biology andMedicine vol 2 no 2 pp 121ndash1262006

[212] K Sunada T Watanabe and K Hashimoto ldquoStudies on pho-tokilling of bacteria on TiO

2thin filmrdquo Journal of Photochem-

istry and Photobiology A Chemistry vol 156 no 1ndash3 pp 227ndash233 2003

[213] J Kiwi and V Nadtochenko ldquoEvidence for the mechanism ofphotocatalytic degradation of the bacterial wall membrane atthe TiO

2interface byATR-FTIR and laser kinetic spectroscopyrdquo

Langmuir vol 21 no 10 pp 4631ndash4641 2005[214] S-H Lee S Pumprueg BMoudgil andW Sigmund ldquoInactiva-

tion of bacterial endospores by photocatalytic nanocompositesrdquoColloids and Surfaces B Biointerfaces vol 40 no 2 pp 93ndash982005

[215] D M A Alrousan P S M Dunlop T A McMurray and J AByrne ldquoPhotocatalytic inactivation of E coli in surface water


using immobilised nanoparticle TiO2filmsrdquo Water Research

vol 43 no 1 pp 47ndash54 2009[216] A Kubacka M Ferrer M L Cerrada et al ldquoBoosting

TiO2-anatase antimicrobial activity polymer-oxide thin filmsrdquo

Applied Catalysis B Environmental vol 89 no 3-4 pp 441ndash4472009

[217] Y Zhu T Ran Y Li J Guo and W Li ldquoDependence of thecytotoxicity of multi-walled carbon nanotubes on the culturemediumrdquo Nanotechnology vol 17 no 18 article 024 pp 4668ndash4674 2006

[218] S Deng V K K Upadhyayula G B Smith andM C MitchellldquoAdsorption equilibrium and kinetics of microorganisms onsingle-wall carbon nanotubesrdquo IEEE Sensors Journal vol 8 no6 pp 954ndash962 2008

[219] D Nepal S Balasubramanian A L Simonian and V A DavisldquoStrong antimicrobial coatings single-walled carbon nanotubesarmored with biopolymersrdquoNano Letters vol 8 no 7 pp 1896ndash1901 2008

[220] V K K Upadhyayula S DengM CMitchell G B Smith V KNair and S Ghoshroy ldquoAdsorption kinetics of Escherichia coliand Staphylococcus aureus on single-walled carbon nanotubeaggregatesrdquoWater Science andTechnology vol 58 no 1 pp 179ndash184 2008

[221] V K K Upadhyayula S Ghoshroy V S Nair G B SmithM C Mitchell and S Deng ldquoSingle-walled carbon nanotubesas fluorescence biosensors for pathogen recognition in watersystemsrdquo Research Letters in Nanotechnology vol 2008 ArticleID 156358 5 pages 2008

[222] T Akasaka and FWatari ldquoCapture of bacteria by flexible carbonnanotubesrdquo Acta Biomaterialia vol 5 no 2 pp 607ndash612 2009

[223] A S Brady-Estevez S Kang and M Elimelech ldquoA single-walled-carbon-nanotube filter for removal of viral and bacterialpathogensrdquo Small vol 4 no 4 pp 481ndash484 2008

[224] S TMostafavi M RMehrnia and AM Rashidi ldquoPreparationof nanofilter from carbon nanotubes for application in virusremoval fromwaterrdquoDesalination vol 238 no 1ndash3 pp 271ndash2802009

[225] R Q Long and R T Yang ldquoCarbon nanotubes as superiorsorbent for dioxin removalrdquo Journal of the American ChemicalSociety vol 123 no 9 pp 2058ndash2059 2001

[226] H YanG PanH Zou X Li andHChen ldquoEffective removal ofmicrocystins using carbon nanotubes embedded with bacteriardquoChinese Science Bulletin vol 49 no 16 pp 1694ndash1698 2004

[227] C Ye Q Gong F Lu and J Liang ldquoAdsorption of middlemolecular weight toxins on carbon nanotubesrdquo Acta PhysicomdashChimica Sinica vol 23 no 9 pp 1321ndash1324 2007

[228] E C de Albuquerque Jr M O A Mendez A dos ReisCoutinho and T T Franco ldquoRemoval of cyanobacteria toxinsfrom drinking water by adsorption on activated carbon fibersrdquoMaterials Research vol 11 no 3 pp 371ndash380 2008

[229] V K K Upadhyayula S Deng M C Mitchell and G B SmithldquoApplication of carbon nanotube technology for removal ofcontaminants in drinking water a reviewrdquo Science of the TotalEnvironment vol 408 no 1 pp 1ndash13 2009

[230] S Kang M Pinault L D Pfefferle and M Elimelech ldquoSingle-walled carbon nanotubes exhibit strong antimicrobial activityrdquoLangmuir vol 23 no 17 pp 8670ndash8673 2007

[231] S Kang M Herzberg D F Rodrigues and M ElimelechldquoAntibacterial effects of carbon nanotubes size does matterrdquoLangmuir vol 24 no 13 pp 6409ndash6413 2008

[232] PWick P Manser L K Limbach et al ldquoThe degree and kind ofagglomeration affect carbon nanotube cytotoxicityrdquo ToxicologyLetters vol 168 no 2 pp 121ndash131 2007

[233] C D Vecitis K R Zodrow S Kang and M ElimelechldquoElectronic-structure-dependent bacterial cytotoxicity ofsingle-walled carbon nanotubesrdquo ACS Nano vol 4 no 9 pp5471ndash5479 2010

[234] S Kang M S Mauter and M Elimelech ldquoPhysicochemicaldeterminants of multiwalled carbon nanotube bacterial cyto-toxicityrdquo Environmental Science and Technology vol 42 no 19pp 7528ndash7534 2008

[235] L R Arias and L Yang ldquoInactivation of bacterial pathogens bycarbon nanotubes in suspensionsrdquo Langmuir vol 25 no 5 pp3003ndash3012 2009

[236] G Jia HWang L Yan et al ldquoCytotoxicity of carbon nanomate-rials single-wall nanotube multi-wall nanotube and fullerenerdquoEnvironmental Science and Technology vol 39 no 5 pp 1378ndash1383 2005

[237] K Donaldson R Aitken L Tran et al ldquoCarbon nanotubes areview of their properties in relation to pulmonary toxicologyand workplace safetyrdquo Toxicological Sciences vol 92 no 1 pp5ndash22 2006

[238] H Dumortier S Lacotte G Pastorin et al ldquoFunctionalized car-bon nanotubes are non-cytotoxic and preserve the functionalityof primary immune cellsrdquo Nano Letters vol 6 no 7 pp 1522ndash1528 2006

[239] M Endo T Hayashi and Y-A Kim ldquoLarge-scale productionof carbon nanotubes and their applicationsrdquo Pure and AppliedChemistry vol 78 no 9 pp 1703ndash1713 2006

[240] J B Nuzzo ldquoThe biological threat to US water supplies towarda national water security policyrdquo Biosecurity and Bioterrorismvol 4 no 2 pp 147ndash159 2006

[241] J J Niu J N Wang Y Jiang L F Su and J Ma ldquoAn approachto carbon nanotubes with high surface area and large porevolumerdquo Microporous and Mesoporous Materials vol 100 no1ndash3 pp 1ndash5 2007

[242] S Kar R C Bindal S Prabhakar P K Tewari K Dasguptaand D Sathiyamoorthy ldquoPotential of carbon nanotubes inwater purification an approach towards the development of anintegrated membrane systemrdquo International Journal of NuclearDesalination vol 3 no 2 pp 143ndash150 2008

[243] M L Jugan L Oziol M Bimbot et al ldquoIn vitro assessmentof thyroid and estrogenic endocrine disruptors in wastewatertreatment plants rivers and drinking water supplies in thegreater Paris area (France)rdquo Science of the Total Environmentvol 407 no 11 pp 3579ndash3587 2009

[244] H Liu J Ru J Qu R Dai Z Wang and C Hu ldquoRemovalof persistent organic pollutants from micro-polluted drinkingwater by triolein embedded absorbentrdquo Bioresource Technologyvol 100 no 12 pp 2995ndash3002 2009

[245] A S Brady-Estevez M H Schnoor S Kang andM ElimelechldquoSWNT-MWNT hybrid filter attains high viral removal andbacterial inactivationrdquo Langmuir vol 26 no 24 pp 19153ndash19158 2010

[246] C D Vecitis M H Schnoor M S Rahaman J D Schiffmanand M Elimelech ldquoElectrochemical multiwalled carbon nan-otube filter for viral and bacterial removal and inactivationrdquoEnvironmental Science and Technology vol 45 no 8 pp 3672ndash3679 2011

[247] M S Rahaman C D Vecitis andM Elimelech ldquoElectrochem-ical carbon-nanotube filter performance toward virus removal


and inactivation in the presence of natural organic matterrdquoEnvironmental Science and Technology vol 46 no 3 pp 1556ndash1564 2012

[248] F Ahmed C M Santos R A M V Vergara M C R TriaR Advincula and D F Rodrigues ldquoAntimicrobial applicationsof electroactive PVK-SWNT nanocompositesrdquo EnvironmentalScience and Technology vol 46 no 3 pp 1804ndash1810 2012

[249] A Tiraferri C D Vecitis and M Elimelech ldquoCovalent bindingof single-walled carbon nanotubes to polyamidemembranes forantimicrobial surface propertiesrdquo ACS Applied Materials andInterfaces vol 3 no 8 pp 2869ndash2877 2011

[250] P Gong H Li X He et al ldquoPreparation and antibacterialactivity of Fe3O4Ag nanoparticlesrdquo Nanotechnology vol 18no 28 Article ID 285604 2007

[251] W-J Chen P-J Tsai and Y-C Chen ldquoFunctional Fe3O4TiO2coreshell magnetic nanoparticles as photokilling agents forpathogenic bacteriardquo Small vol 4 no 4 pp 485ndash491 2008

[252] O B Koper J S Klabunde G L Marchin K J Klabunde PStoimenov andL Bohra ldquoNanoscale powders and formulationswith biocidal activity toward spores and vegetative cells ofBacillus species viruses and toxinsrdquo Current Microbiology vol44 no 1 pp 49ndash55 2002

[253] PK Stoimenov R L KlingerG LMarchin andK J KlabundeldquoMetal oxide nanoparticles as bactericidal agentsrdquo Langmuirvol 18 no 17 pp 6679ndash6686 2002

[254] M A Gondal M A Dastageer and A Khalil ldquoSynthesis ofnano-WO3 and its catalytic activity for enhanced antimicrobialprocess for water purification using laser induced photo-catalysisrdquo Catalysis Communications vol 11 no 3 pp 214ndash2192009

[255] A KhalilM A Gondal andMADastageer ldquoAugmented pho-tocatalytic activity of palladium incorporated ZnO nanoparti-cles in the disinfection of Escherichia coli microorganism fromwaterrdquo Applied Catalysis A General vol 402 no 1-2 pp 162ndash167 2011

[256] H Bai Z liu and D D Sun ldquoHierarchical ZnO nanostruc-tured membrane for multifunctional environmental applica-tionsrdquoColloids and Surfaces A Physicochemical and EngineeringAspects vol 410 pp 11ndash17 2012

[257] T Humplik J Lee S C OHern et al ldquoNanostructuredmaterials for water desalinationrdquo Nanotechnology vol 22 no29 Article ID 292001 2011

[258] C Fritzmann J Lowenberg T Wintgens and T Melin ldquoState-of-the-art of reverse osmosis desalinationrdquo Desalination vol216 no 1ndash3 pp 1ndash76 2007

[259] M S Mohsen J O Jaber and M D Afonso ldquoDesalination ofbrackish water by nanofiltration and reverse osmosisrdquo Desali-nation vol 157 no 1ndash3 p 167 2003

[260] A Srivastava O N Srivastava S Talapatra R Vajtai and P MAjayan ldquoCarbon nanotube filtersrdquo Nature Materials vol 3 no9 pp 610ndash614 2004

[261] J K Holt H G Park Y Wang et al ldquoFast mass transportthrough sub-2-nanometer carbon nanotubesrdquo Science vol 312no 5776 pp 1034ndash1037 2006

[262] F Fornasiero G P Hyung J K Holt et al ldquoIon exclusion bysub-2-nm carbon nanotube poresrdquo Proceedings of the NationalAcademy of Sciences of the United States of America vol 105 no45 pp 17250ndash17255 2008

[263] L Li J Dong TMNenoff and R Lee ldquoDesalination by reverseosmosis using MFI zeolite membranesrdquo Journal of MembraneScience vol 243 no 1-2 pp 401ndash404 2004

[264] L Li N Liu B McPherson and R Lee ldquoInfluence of counterions on the reverse osmosis through MFI zeolite membranesimplications for produced water desalinationrdquo Desalinationvol 228 no 1ndash3 pp 217ndash225 2008

[265] K Sint B Wang and P Kral ldquoSelective ion passage throughfunctionalized graphene nanoporesrdquo Journal of the AmericanChemical Society vol 130 no 49 pp 16448ndash16449 2008

[266] D-E Jiang V R Cooper and S Dai ldquoPorous graphene as theultimate membrane for gas separationrdquo Nano Letters vol 9 no12 pp 4019ndash4024 2009

[267] J Bai X Zhong S Jiang Y Huang and X Duan ldquoGraphenenanomeshrdquo Nature Nanotechnology vol 5 no 3 pp 190ndash1942010

[268] C L Pint S T Pheasant M Pasquali K E Coulter H KSchmidt and R H Hauge ldquoSynthesis of high aspect-ratiocarbon nanotube ldquoflying carpetsrdquo from nanostructured flakesubstratesrdquo Nano Letters vol 8 no 7 pp 1879ndash1883 2008

[269] N Arjmandi P Sasanpour and B Rashidian ldquoCVD synthesisof small-diameter Single-Walled carbon nanotubes on siliconrdquoScientia Iranica vol 16 no 1 D pp 61ndash64 2009

[270] C Song and B Corry ldquoIntrinsic ion selectivity of narrowhydrophobic poresrdquo Journal of Physical Chemistry B vol 113 no21 pp 7642ndash7649 2009

[271] H S Lee S J Im J H Kim H J Kim J P Kim andB R Min ldquoPolyamide thin-film nanofiltration membranescontaining TiO

2nanoparticlesrdquo Desalination vol 219 no 1ndash3

pp 48ndash56 2008[272] M M Cortalezzi J Rose A R Barron and M R Wiesner

ldquoCharacteristics of ultrafiltration ceramic membranes derivedfrom alumoxane nanoparticlesrdquo Journal of Membrane Sciencevol 205 no 1-2 pp 33ndash43 2002

[273] B S Karnik S H Davies M J Baumann and S J Mas-ten ldquoFabrication of catalytic membranes for the treatment ofdrinking water using combined ozonation and ultrafiltrationrdquoEnvironmental Science and Technology vol 39 no 19 pp 7656ndash7661 2005

[274] M C Duke S Mee and J C D da Costa ldquoPerformanceof porous inorganic membranes in non-osmotic desalinationrdquoWater Research vol 41 no 17 pp 3998ndash4004 2007

[275] B-H Jeong E M V Hoek Y Yan et al ldquoInterfacial polymer-ization of thin film nanocomposites a new concept for reverseosmosismembranesrdquo Journal ofMembrane Science vol 294 no1-2 pp 1ndash7 2007

[276] L Li and R Lee ldquoPurification of produced water by ceramicmembranes material screening process design and eco-nomicsrdquo Separation Science and Technology vol 44 no 15 pp3455ndash3484 2009

[277] M E Suk and N R Aluru ldquoWater transport through ultrathingraphenerdquo Journal of Physical Chemistry Letters vol 1 no 10pp 1590ndash1594 2010

[278] X Gong J Li H Lu et al ldquoA charge-driven molecular waterpumprdquo Nature Nanotechnology vol 2 no 11 pp 709ndash712 2007

[279] C C Striemer T R Gaborski J L McGrath and P M FauchetldquoCharge- and size-based separation of macromolecules usingultrathin silicon membranesrdquo Nature vol 445 no 7129 pp749ndash753 2007

[280] G Zuo R Shen S Ma and W Guo ldquoTransport properties ofsingle-file water molecules inside a carbon nanotube biomim-icking water channelrdquoACSNano vol 4 no 1 pp 205ndash210 2010

[281] E M V Hoek and A K Ghosh ldquoNanotechnology-BasedMem-branes for Water Purificationrdquo in Nanotechnology Applications


for Clean Water N Savage M Diallo J Duncan A Street andR Sustich Eds chapter 4 pp 47ndash58 William Andrew BostonMass USA 2009

[282] M L Lind A K Ghosh A Jawor et al ldquoInfluence of zeolitecrystal size on zeolite-polyamide thin film nanocompositemembranesrdquo Langmuir vol 25 no 17 pp 10139ndash10145 2009

[283] M L Lind D E Suk T-V Nguyen and E M V Hoek ldquoTai-loring the structure of thin film nanocomposite membranes toachieve seawater RO membrane performancerdquo EnvironmentalScience and Technology vol 44 no 21 pp 8230ndash8235 2010

[284] P Nednoor N Chopra V Gavalas L G Bachas and B J HindsldquoReversible biochemical switching of ionic transport throughaligned carbon nanotube membranesrdquo Chemistry of Materialsvol 17 no 14 pp 3595ndash3599 2005

[285] M S Mauter and M Elimelech ldquoEnvironmental applicationsof carbon-based nanomaterialsrdquo Environmental Science andTechnology vol 42 no 16 pp 5843ndash5859 2008

[286] B Hinds ldquoDramatic transport properties of carbon nanotubemembranes for a robust protein channel mimetic platformrdquoCurrent Opinion in Solid State andMaterials Science vol 16 no1 pp 1ndash9 2012

[287] G P Rao C Lu and F Su ldquoSorption of divalentmetal ions fromaqueous solution by carbon nanotubes a reviewrdquo Separationand Purification Technology vol 58 no 1 pp 224ndash231 2007

[288] Y-H Li J Ding Z Luan et al ldquoCompetitive adsorptionof Pb2+ Cu2+ and Cd 2+ ions from aqueous solutions bymultiwalled carbon nanotubesrdquo Carbon vol 41 no 14 pp2787ndash2792 2003

[289] Z-C Di J Ding X-J Peng Y-H Li Z-K Luan and J LiangldquoChromiumadsorption by aligned carbonnanotubes supportedceria nanoparticlesrdquo Chemosphere vol 62 no 5 pp 861ndash8652006

[290] Y-H Li Z Di J Ding DWu Z Luan and Y Zhu ldquoAdsorptionthermodynamic kinetic and desorption studies of Pb2+ oncarbon nanotubesrdquoWater Research vol 39 no 4 pp 605ndash6092005

[291] C Lu H Chiu and C Liu ldquoRemoval of zinc(II) from aqueoussolution by purified carbonnanotubes kinetics and equilibriumstudiesrdquo Industrial and Engineering Chemistry Research vol 45no 8 pp 2850ndash2855 2006

[292] X Peng Z Luan J Ding Z Di Y Li and B Tian ldquoCeriananoparticles supported on carbon nanotubes for the removalof arsenate fromwaterrdquoMaterials Letters vol 59 no 4 pp 399ndash403 2005

[293] C Lu Y-L Chung and K-F Chang ldquoAdsorption of tri-halomethanes from water with carbon nanotubesrdquo WaterResearch vol 39 no 6 pp 1183ndash1189 2005

[294] C Lu and H Chiu ldquoAdsorption of zinc(II) from water withpurified carbon nanotubesrdquo Chemical Engineering Science vol61 no 4 pp 1138ndash1145 2006

[295] K L Salipira B B Mamba R W Krause T J Malefetse andS H Durbach ldquoCarbon nanotubes and cyclodextrin polymersfor removing organic pollutants from waterrdquo EnvironmentalChemistry Letters vol 5 no 1 pp 13ndash17 2007

[296] Y C Sharma V Srivastava V K Singh S N Kaul and C HWeng ldquoNano-adsorbents for the removal of metallic pollutantsfrom water and wastewaterrdquo Environmental Technology vol 30no 6 pp 583ndash609 2009

[297] E A Deliyanni D N Bakoyannakis A I Zouboulis and KA Matis ldquoSorption of As(V) ions by akaganeite-type nanocrys-talsrdquo Chemosphere vol 50 no 1 pp 155ndash163 2003

[298] J T Mayo C Yavuz S Yean et al ldquoThe effect of nanocrystallinemagnetite size on arsenic removalrdquo Science and Technology ofAdvanced Materials vol 8 no 1-2 pp 71ndash75 2007

[299] K Kabra R Chaudhary and R L Sawhney ldquoTreatment ofhazardous organic and inorganic compounds through aqueous-phase photocatalysis a reviewrdquo Industrial and EngineeringChemistry Research vol 43 no 24 pp 7683ndash7696 2004

[300] M E Pena G P Korfiatis M Patel L Lippincott and XMengldquoAdsorption of As(V) and As(III) by nanocrystalline titaniumdioxiderdquoWater Research vol 39 no 11 pp 2327ndash2337 2005

[301] K Zhang K C Kemp andV Chandra ldquoHomogeneous anchor-ing of TiO

2nanoparticles on graphene sheets for waste water

treatmentrdquoMaterials Letters vol 81 pp 127ndash130 2012[302] M A Omole I KrsquoOwino and O A Sadik ldquoNanostructured

materials for improving water quality potentials and risksrdquo inNanotechnology Applications for Clean Water N Savage MDiallo J Duncan A Street and R Sustich Eds chapter 17 pp233ndash247 William Andrew Boston Mass USA 2009

[303] C H Lai and C Y Chen ldquoRemoval of metal ions and humicacid from water by iron-coated filter mediardquo Chemosphere vol44 no 5 pp 1177ndash1184 2001

[304] M S Onyango Y Kojima H Matsuda and A OchiengldquoAdsorption kinetics of arsenic removal from groundwater byiron-modified zeoliterdquo Journal of Chemical Engineering of Japanvol 36 no 12 pp 1516ndash1522 2003

[305] L C A Oliveira D I Petkowicz A Smaniotto and S B CPergher ldquoMagnetic zeolites a new adsorbent for removal ofmetallic contaminants from waterrdquoWater Research vol 38 no17 pp 3699ndash3704 2004

[306] C T Yavuz J T Mayo W W Yu et al ldquoLow-field magneticseparation of monodisperse Fe3O4 nanocrystalsrdquo Science vol314 no 5801 pp 964ndash967 2006

[307] M Takafuji S Ide H Ihara and Z Xu ldquoPreparation of poly(1-vinylimidazole)-graftedmagnetic nanoparticles and their appli-cation for removal ofmetal ionsrdquoChemistry ofMaterials vol 16no 10 pp 1977ndash1983 2004

[308] L Wang Z Yang J Gao et al ldquoA biocompatible method ofdecorporation bisphosphonate-modifiedmagnetite nanoparti-cles to remove uranyl ions from bloodrdquo Journal of the AmericanChemical Society vol 128 no 41 pp 13358ndash13359 2006

[309] S M Ponder J G Darab and T E Mallouk ldquoRemediationof Cr(VI) and Pb(II) aqueous solutions using supportednanoscale zero-valent ironrdquoEnvironmental Science andTechnol-ogy vol 34 no 12 pp 2564ndash2569 2000

[310] S R Kanel B Manning L Charlet and H Choi ldquoRemoval ofarsenic(III) from groundwater by nanoscale zero-valent ironrdquoEnvironmental Science and Technology vol 39 no 5 pp 1291ndash1298 2005

[311] S R Kanel J-M Greneche and H Choi ldquoArsenic(V) removalfrom groundwater using nano scale zero-valent iron as acolloidal reactive barrier materialrdquo Environmental Science andTechnology vol 40 no 6 pp 2045ndash2050 2006

[312] G C C Yang and H-L Lee ldquoChemical reduction of nitrate bynanosized iron kinetics and pathwaysrdquoWater Research vol 39no 5 pp 884ndash894 2005

[313] X-Q Li and W-X Zhang ldquoIron nanoparticles the core-shell structure and unique properties for Ni(II) sequestrationrdquoLangmuir vol 22 no 10 pp 4638ndash4642 2006

[314] W Zhang ldquoNanoscale iron particles for environmental remedi-ation an overviewrdquo Journal of Nanoparticle Research vol 5 no3-4 pp 323ndash332 2003


[315] L S Zhong J S HuH P Liang AM CaoWG Song and L JWan ldquoSelf-assembled 3D flowerlike iron oxide nanostructuresand their application in water treatmentrdquo Advanced Materialsvol 18 no 18 pp 2426ndash2431 2006

[316] L-S Zhong J-S Hu A-M Cao Q Liu W-G Song and L-JWan ldquo3D flowerlike ceria micronanocomposite structure andits application for water treatment and CO removalrdquo Chemistryof Materials vol 19 no 7 pp 1648ndash1655 2007

[317] N Moreno X Querol C Ayora C F Pereira and M Janssen-Jurkovicova ldquoUtilization of zeolites synthesized from coal flyash for the purification of acid mine watersrdquo EnvironmentalScience and Technology vol 35 no 17 pp 3526ndash3534 2001

[318] E Alvarez-Ayuso A Garcıa-Sanchez and X Querol ldquoPurifica-tion of metal electroplating waste waters using zeolitesrdquo WaterResearch vol 37 no 20 pp 4855ndash4862 2003

[319] M S Diallo S Christie P Swaminathan et al ldquoDendriticchelating agents 1 Cu(II) binding to ethylene diamine corepoly(amidoamine) dendrimers in aqueous solutionsrdquo Lang-muir vol 20 no 7 pp 2640ndash2651 2004

[320] S V Mattigod X Feng G E Fryxell J Liu and M GongldquoSeparation of complexed mercury from aqueous wastes usingself-assembled mercaptan on mesoporous silicardquo SeparationScience and Technology vol 34 no 12 pp 2329ndash2345 1999

[321] W Yantasee Y Lin G E Fryxell B J Busche and J CBirnbaum ldquoRemoval of heavy metals from aqueous solu-tion using novel nanoengineered sorbents self-assembled car-bamoylphosphonic acids on mesoporous silicardquo SeparationScience and Technology vol 38 no 15 pp 3809ndash3825 2003

[322] S V Mattigod G E Fryxell X Feng K E Parker and E MPiers ldquoRemoval of mercury from aqueous streams of fossil fuelpower plants using novel functionalized nanoporous sorbentsrdquoin Coal Combustion Byproducts and Environmental Issues K SSajwan I Twardowska T Punshon and A K Alva Eds pp99ndash104 Springer New York NY USA 2006

[323] J Kostal A Mulchandani andW Chen ldquoTunable biopolymersfor heavy metal removalrdquo Macromolecules vol 34 no 7 pp2257ndash2261 2001

[324] J Kostal A Mulchandani K E Gropp and W Chen ldquoAtemperature responsive biopolymer for mercury remediationrdquoEnvironmental Science and Technology vol 37 no 19 pp 4457ndash4462 2003

[325] L Qi and Z Xu ldquoLead sorption from aqueous solutions on chi-tosan nanoparticlesrdquo Colloids and Surfaces A Physicochemicaland Engineering Aspects vol 251 no 1ndash3 pp 183ndash190 2004

[326] B Van Der Bruggen and C Vandecasteele ldquoRemoval of pol-lutants from surface water and groundwater by nanofiltrationoverview of possible applications in the drinking water indus-tryrdquo Environmental Pollution vol 122 no 3 pp 435ndash445 2003

[327] A Favre-Reguillon G Lebuzit J Foos A Guy M Draye andM Lemaire ldquoSelective concentration of uranium from sea-water by nanofiltrationrdquo Industrial and Engineering ChemistryResearch vol 42 no 23 pp 5900ndash5904 2003

[328] K D Hristovski H Nguyen and P K Westerhoff ldquoRemovalof arsenate and 17120572-ethinyl estradiol (EE2) by iron (hydr)oxidemodified activated carbon fibersrdquo Journal of EnvironmentalScience and HealthmdashPart A ToxicHazardous Substances andEnvironmental Engineering vol 44 no 4 pp 354ndash361 2009

[329] K D Hristovski P K Westerhoff T Moller and P SylvesterldquoEffect of synthesis conditions on nano-iron (hydr)oxideimpregnated granulated activated carbonrdquo Chemical Engineer-ing Journal vol 146 no 2 pp 237ndash243 2009

[330] M S Diallo S Christie P Swaminathan J H Johnson Jrand W A Goddard III ldquoDendrimer enhanced ultrafiltration1Recovery of Cu(II) from aqueous solutions using PAMAMdendrimers with ethylene diamine core and terminal NH2groupsrdquo Environmental Science and Technology vol 39 no 5pp 1366ndash1377 2005

[331] M J Aragon R L Everett M D Siegel et al ldquoArsenic pilotplant operation and resultsrdquo SAND 2007-6059 Sandia NationalLaboratories Anthony NM USA 2007

[332] P Sylvester P Westerhoff T Moller M Badruzzaman and OBoyd ldquoA hybrid sorbent utilizing nanoparticles of hydrous ironoxide for arsenic removal from drinking waterrdquo EnvironmentalEngineering Science vol 24 no 1 pp 104ndash112 2007

[333] C Charnock and O Kjoslashnnoslash ldquoAssimilable organic carbon andbiodegradable dissolved organic carbon in Norwegian raw anddrinking watersrdquoWater Research vol 34 no 10 pp 2629ndash26422000

[334] J Frias F Ribas and F Lucena ldquoEffects of different nutrientson bacterial growth in a pilot distribution systemrdquo Antonie vanLeeuwenhoek International Journal of General and MolecularMicrobiology vol 80 no 2 pp 129ndash138 2001

[335] F Li A Yuasa K Ebie Y Azuma T Hagishita and Y MatsuildquoFactors affecting the adsorption capacity of dissolved organicmatter onto activated carbon modified isotherm analysisrdquoWater Research vol 36 no 18 pp 4592ndash4604 2002

[336] M J Lehtola T Juhna I T Miettinen T Vartiainen andP J Martikainen ldquoFormation of biofilms in drinking waterdistribution networks a case study in two cities in Finland andLatviardquo Journal of Industrial Microbiology and Biotechnologyvol 31 no 11 pp 489ndash494 2004

[337] B Schreiber T Brinkmann V Schmalz and EWorch ldquoAdsorp-tion of dissolved organic matter onto activated carbonmdashtheinfluence of temperature absorption wavelength and molecu-lar sizerdquoWater Research vol 39 no 15 pp 3449ndash3456 2005

[338] A Matilainen N Vieno and T Tuhkanen ldquoEfficiency ofthe activated carbon filtration in the natural organic matterremovalrdquo Environment International vol 32 no 3 pp 324ndash3312006

[339] C Lu and F Su ldquoAdsorption of natural organicmatter by carbonnanotubesrdquo Separation and Purification Technology vol 58 no1 pp 113ndash121 2007

[340] S A Dastgheib T Karanfil andW Cheng ldquoTailoring activatedcarbons for enhanced removal of natural organic matter fromnatural watersrdquo Carbon vol 42 no 3 pp 547ndash557 2004

[341] P A Quinlivan L Li and D R U Knappe ldquoEffects ofactivated carbon characteristics on the simultaneous adsorptionof aqueous organicmicropollutants and natural organicmatterrdquoWater Research vol 39 no 8 pp 1663ndash1673 2005

[342] W Cheng S A Dastgheib and T Karanfil ldquoAdsorption of dis-solved natural organic matter by modified activated carbonsrdquoWater Research vol 39 no 11 pp 2281ndash2290 2005

[343] H Hyung and J-H Kim ldquoNatural organic matter (NOM)adsorption to multi-walled carbon nanotubes effect of NOMcharacteristics and water quality parametersrdquo EnvironmentalScience and Technology vol 42 no 12 pp 4416ndash4421 2008

[344] N B Saleh L D Pfefferle and M Elimelech ldquoAggregationkinetics of multiwalled carbon nanotubes in aquatic systemsmeasurements and environmental implicationsrdquoEnvironmentalScience and Technology vol 42 no 21 pp 7963ndash7969 2008

[345] X M Yan B Y Shi J J Lu C H Feng D S Wang andH X Tang ldquoAdsorption and desorption of atrazine on carbon


nanotubesrdquo Journal of Colloid and Interface Science vol 321 no1 pp 30ndash38 2008

[346] T G Hedderman S M Keogh G Chambers and H J ByrneldquoIn-depth study into the interaction of single walled carbonnanotubeswith anthracene and p-terphenylrdquo Journal of PhysicalChemistry B vol 110 no 9 pp 3895ndash3901 2006

[347] K Yang L Zhu andB Xing ldquoAdsorption of polycyclic aromatichydrocarbons by carbon nanomaterialsrdquo Environmental Scienceand Technology vol 40 no 6 pp 1855ndash1861 2006

[348] S Gotovac C-M Yang Y Hattori K Takahashi H Kanohand K Kaneko ldquoAdsorption of polyaromatic hydrocarbons onsingle wall carbon nanotubes of different functionalities anddiametersrdquo Journal of Colloid and Interface Science vol 314 no1 pp 18ndash24 2007

[349] C LMangun Z Yue J Economy SMaloney P Kemme andDCropek ldquoAdsorption of organic contaminants from water usingtailored ACFsrdquo Chemistry of Materials vol 13 no 7 pp 2356ndash2360 2001

[350] X Peng Y Li Z Luan et al ldquoAdsorption of 12-dichlorobenzenefrom water to carbon nanotubesrdquo Chemical Physics Letters vol376 no 1-2 pp 154ndash158 2003

[351] C Lu Y-L Chung and K-F Chang ldquoAdsorption thermody-namic and kinetic studies of trihalomethanes on multiwalledcarbon nanotubesrdquo Journal of HazardousMaterials vol 138 no2 pp 304ndash310 2006

[352] Y-Q Cai Y-E Cai S-F Mou and Y-Q Lu ldquoMulti-walledcarbon nanotubes as a solid-phase extraction adsorbent forthe determination of chlorophenols in environmental watersamplesrdquo Journal of Chromatography A vol 1081 no 2 pp 245ndash247 2005

[353] Q Zhou J Xiao and W Wang ldquoUsing multi-walled carbonnanotubes as solid phase extraction adsorbents to determinedichlorodiphenyltrichloroethane and its metabolites at tracelevel inwater samples by high performance liquid chromatogra-phy with UV detectionrdquo Journal of Chromatography A vol 1125no 2 pp 152ndash158 2006

[354] Q Zhou J Xiao W Wang G Liu Q Shi and J WangldquoDetermination of atrazine and simazine in environmentalwater samples using multiwalled carbon nanotubes as theadsorbents for preconcentration prior to high performanceliquid chromatography with diode array detectorrdquo Talanta vol68 no 4 pp 1309ndash1315 2006

[355] M Zhou P R Nemade X Lu et al ldquoNew type of membranematerial for water desalination based on a cross-linked bicon-tinuous cubic lyotropic liquid crystal assemblyrdquo Journal of theAmerican Chemical Society vol 129 no 31 pp 9574ndash9575 2007

[356] J Nawrocki and B Kasprzyk-Hordern ldquoThe efficiency andmechanisms of catalytic ozonationrdquo Applied Catalysis B Envi-ronmental vol 99 no 1-2 pp 27ndash42 2010

[357] C A Orge J J M Orfao M F R Pereira A M Duartede Farias R C R Neto and M A Fraga ldquoOzonation ofmodel organic compounds catalysed by nanostructured ceriumoxidesrdquo Applied Catalysis B Environmental vol 103 no 1-2 pp190ndash199 2011

[358] N Chitose S Ueta S Seino and T A Yamamoto ldquoRadiolysisof aqueous phenol solutions with nanoparticles 1 Phenoldegradation and TOC removal in solutions containing TiO

2

induced by UV 120574-ray and electron beamsrdquo Chemosphere vol50 no 8 pp 1007ndash1013 2003

[359] J Jin R Li HWangH Chen K Liang and JMa ldquoMagnetic Fenanoparticle functionalized water-soluble multi-walled carbon

nanotubules towards the preparation of sorbent for aromaticcompounds removalrdquo Chemical Communications no 4 pp386ndash388 2007

[360] X Han Q Kuang M Jin Z Xie and L Zheng ldquoSynthesisof titania nanosheets with a high percentage of exposed (001)facets and related photocatalytic propertiesrdquo Journal of theAmerican Chemical Society vol 131 no 9 pp 3152ndash3153 2009

[361] N Murakami Y Kurihara T Tsubota and T Ohno ldquoShape-controlled anatase titanium(IV) oxide particles prepared byhydrothermal treatment of peroxo titanic acid in the presenceof polyvinyl alcoholrdquo Journal of Physical Chemistry C vol 113no 8 pp 3062ndash3069 2009

[362] S Liu J Yu and M Jaroniec ldquoAnatase TiO2with dominant

high-energy 001 facets synthesis properties and applicationsrdquoChemistry of Materials vol 23 no 18 pp 4085ndash4093 2011

[363] S Iwamoto W Tanakulrungsank M Inoue K Kagawa andP Praserthdam ldquoSynthesis of large-surface area silica-modifiedtitania ultrafine particles by the glycothermal methodrdquo Journalof Materials Science Letters vol 19 no 16 pp 1439ndash1443 2000

[364] S Iwamoto S Iwamoto M Inoue H Yoshida T Tanaka andK Kagawa ldquoXANES and XPS study of silica-modified titaniasprepared by the glycothermal methodrdquo Chemistry of Materialsvol 17 no 3 pp 650ndash655 2005

[365] H Liu and L Gao ldquoSynthesis and properties of CdSe-sensitizedrutile TiO

2nanocrystals as a visible light-responsive photocata-

lystrdquo Journal of the American Ceramic Society vol 88 no 4 pp1020ndash1022 2005

[366] L Wu J C Yu and X Fu ldquoCharacterization and photocatalyticmechanism of nanosized CdS coupled TiO

2nanocrystals under

visible light irradiationrdquo Journal of Molecular Catalysis AChemical vol 244 no 1-2 pp 25ndash32 2006

[367] Y Liu X Chen J Li and C Burda ldquoPhotocatalytic degradationof azo dyes by nitrogen-doped TiO

2nanocatalystsrdquo Chemo-

sphere vol 61 no 1 pp 11ndash18 2005[368] M S Nahar K Hasegawa and S Kagaya ldquoPhotocatalytic

degradation of phenol by visible light-responsive iron-dopedTiO2and spontaneous sedimentation of the TiO

2particlesrdquo

Chemosphere vol 65 no 11 pp 1976ndash1982 2006[369] D Sun T T Meng T H Loong and T J Hwa ldquoRemoval

of natural organic matter from water using a nano-structuredphotocatalyst coupled with filtration membranerdquoWater Scienceand Technology vol 49 no 1 pp 103ndash110 2004

[370] A Tuel and L G Hubert-Pfalzgraf ldquoNanometric monodis-persed titanium oxide particles onmesoporous silica synthesischaracterization and catalytic activity in oxidation reactions inthe liquid phaserdquo Journal of Catalysis vol 217 no 2 pp 343ndash3532003

[371] M-J Lopez-Munoz R V Grieken J Aguado and J MaruganldquoRole of the support on the activity of silica-supported TiO

2

photocatalysts structure of the TiO2SBA-15 photocatalystsrdquo

Catalysis Today vol 101 no 3-4 pp 307ndash314 2005[372] X Zhang F Zhang and K-Y Chan ldquoSynthesis of titania-

silica mixed oxide mesoporous materials characterization andphotocatalytic propertiesrdquo Applied Catalysis A General vol284 no 1-2 pp 193ndash198 2005

[373] M Pratap Reddy A Venugopal and M SubrahmanyamldquoHydroxyapatite-supported Ag-TiO

2as Escherichia coli disin-

fection photocatalystrdquo Water Research vol 41 no 2 pp 379ndash386 2007


[374] S K Samantaray P Mohapatra and K Parida ldquoPhysico-chemical characterisation and photocatalytic activity of nano-sized SO42-TiO2 towards degradation of 4-nitrophenolrdquo Jour-nal of Molecular Catalysis A Chemical vol 198 no 1-2 pp 277ndash287 2003

[375] Y Chen J C Crittenden S Hackney L Sutter and DW HandldquoPreparation of a novel TiO

2-based p-n junction nanotube

photocatalystrdquo Environmental Science and Technology vol 39no 5 pp 1201ndash1208 2005

[376] J M Macak M Zlamal J Krysa and P Schmuki ldquoSelf-organized TiO

2nanotube layers as highly efficient photocata-

lystsrdquo Small vol 3 no 2 pp 300ndash304 2007[377] N M Al-Bastaki ldquoPerformance of advanced methods for

treatment of wastewater UVTiO2 RO and UFrdquo Chemical

Engineering and Processing Process Intensification vol 43 no7 pp 935ndash940 2004

[378] M J Benotti B D Stanford E C Wert and S A SnyderldquoEvaluation of a photocatalytic reactor membrane pilot systemfor the removal of pharmaceuticals and endocrine disruptingcompounds fromwaterrdquoWater Research vol 43 no 6 pp 1513ndash1522 2009

[379] PWesterhoffHMoonDMinakata and J Crittenden ldquoOxida-tion of organics in retentates from reverse osmosis wastewaterreuse facilitiesrdquo Water Research vol 43 no 16 pp 3992ndash39982009

[380] X Zhao L Lv B Pan W Zhang S Zhang and Q ZhangldquoPolymer-supported nanocomposites for environmental appli-cation a reviewrdquoChemical Engineering Journal vol 170 no 2-3pp 381ndash394 2011

[381] A F CCampos RAquino TA PGCotta F A Tourinho andJ Depeyrot ldquoUsing speciation diagrams to improve synthesisof magnetic nanosorbents for environmental applicationsrdquoBulletin of Materials Science vol 34 no 7 pp 1357ndash1361 2011

[382] P Li D E Miser S Rabiei R T Yadav and M R HajaligolldquoThe removal of carbonmonoxide by iron oxide nanoparticlesrdquoApplied Catalysis B Environmental vol 43 no 2 pp 151ndash1622003

[383] R Wu J Qu and Y Chen ldquoMagnetic powder MnO-Fe2O3

compositemdashA novel material for the removal of azo-dye fromwaterrdquoWater Research vol 39 no 4 pp 630ndash638 2005

[384] S Qiao D D Sun J H Tay and C Easton ldquoPhotocatalyticoxidation technology for humic acid removal using a nano-structured TiO

2Fe2O3catalystrdquoWater Science and Technology

vol 47 no 1 pp 211ndash217 2003[385] C-B Wang and W-X Zhang ldquoSynthesizing nanoscale iron

particles for rapid and complete dechlorination of TCE andPCBsrdquo Environmental Science and Technology vol 31 no 7 pp2154ndash2156 1997

[386] W-X Zhang C-B Wang and H-L Lien ldquoTreatment ofchlorinated organic contaminants with nanoscale bimetallicparticlesrdquo Catalysis Today vol 40 no 4 pp 387ndash395 1998

[387] R Cheng J-L Wang and W-X Zhang ldquoComparison ofreductive dechlorination of p-chlorophenol using Fe0 andnanosized Fe0rdquo Journal of HazardousMaterials vol 144 no 1-2pp 334ndash339 2007

[388] S Choe Y-Y Chang K-Y Hwang and J Khim ldquoKineticsof reductive denitrification by nanoscale zero-valent ironrdquoChemosphere vol 41 no 8 pp 1307ndash1311 2000

[389] J Cao D Elliott and W-X Zhang ldquoPerchlorate reduction bynanoscale iron particlesrdquo Journal of Nanoparticle Research vol7 no 4-5 pp 499ndash506 2005

[390] S Parra S E Stanca I Guasaquillo and K RavindranathanThampi ldquoPhotocatalytic degradation of atrazine using sus-pended and supported TiO

2rdquo Applied Catalysis B Environmen-

tal vol 51 no 2 pp 107ndash116 2004[391] J Xu and D Bhattacharyya ldquoModeling of FePd nanoparticle-

based functionalizedmembrane reactor for PCBdechlorinationat room temperaturerdquo Journal of Physical Chemistry C vol 112no 25 pp 9133ndash9144 2008

[392] Y Xu and D Zhao ldquoReductive immobilization of chromatein water and soil using stabilized iron nanoparticlesrdquo WaterResearch vol 41 no 10 pp 2101ndash2108 2007

[393] B Schrick J L Blough A D Jones and T E MalloukldquoHydrodechlorination of trichloroethylene to hydrocarbonsusing bimetallic nickel-iron nanoparticlesrdquo Chemistry of Mate-rials vol 14 no 12 pp 5140ndash5147 2002

[394] J T Nurmi P G Tratnyek V Sarathy et al ldquoCharacterizationand properties of metallic iron nanoparticles spectroscopyelectrochemistry and kineticsrdquo Environmental Science andTechnology vol 39 no 5 pp 1221ndash1230 2005

[395] H-L Lien and W-X Zhang ldquoTransformation of chlorinatedmethanes by nanoscale iron particlesrdquo Journal of EnvironmentalEngineering vol 125 no 11 pp 1042ndash1047 1999

[396] S-F Cheng and S-C Wu ldquoThe enhancement methods for thedegradation of TCE by zero-valent metalsrdquo Chemosphere vol41 no 8 pp 1263ndash1270 2000

[397] S-F Cheng and S-C Wu ldquoFeasibility of using metals toremediate water containing TCErdquo Chemosphere vol 43 no 8pp 1023ndash1028 2001

[398] H-L Lien andW-X Zhang ldquoNanoscale iron particles for com-plete reduction of chlorinated ethenesrdquoColloids and Surfaces APhysicochemical andEngineeringAspects vol 191 no 1-2 pp 97ndash105 2001

[399] F He and D Zhao ldquoPreparation and characterization of a newclass of starch-stabilized bimetallic nanoparticles for degra-dation of chlorinated hydrocarbons in waterrdquo EnvironmentalScience and Technology vol 39 no 9 pp 3314ndash3320 2005

[400] B-W Zhu T-T Lim and J Feng ldquoReductive dechlorination of124-trichlorobenzene with palladized nanoscale Fe0 particlessupported on chitosan and silicardquo Chemosphere vol 65 no 7pp 1137ndash1145 2006

[401] J Wei X Xu Y Liu and D Wang ldquoCatalytic hydrodechlo-rination of 24-dichlorophenol over nanoscale PdFe reactionpathway and some experimental parametersrdquo Water Researchvol 40 no 2 pp 348ndash354 2006

[402] T-T Lim J Feng and B-W Zhu ldquoKinetic and mechanisticexaminations of reductive transformation pathways of bromi-nated methanes with nano-scale Fe and NiFe particlesrdquoWaterResearch vol 41 no 4 pp 875ndash883 2007

[403] P V Kamat R Huehn and R Nicolaescu ldquoA ldquosense andshootrdquo approach for photocatalytic degradation of organiccontaminants inwaterrdquo Journal of Physical Chemistry B vol 106no 4 pp 788ndash794 2002

[404] Z-C Wu Y Zhang T-X Tao L Zhang and H FongldquoSilver nanoparticles on amidoxime fibers for photo-catalyticdegradation of organic dyes in waste waterrdquo Applied SurfaceScience vol 257 no 3 pp 1092ndash1097 2010

[405] B P Chaplin E Roundy K A Guy J R Shapley and C IWerth ldquoEffects of natural water ions and humic acid on catalyticnitrate reduction kinetics using an alumina supported Pd-Cucatalystrdquo Environmental Science and Technology vol 40 no 9pp 3075ndash3081 2006


[406] H Hildebrand K Mackenzie and F-D Kopinke ldquoNovel nano-catalysts for wastewater treatmentrdquo Global Nest Journal vol 10no 1 pp 47ndash53 2008

[407] M O Nutt J B Hughes and M S Wong ldquoDesigning Pd-on-Au bimetallic nanoparticle catalysts for trichloroethenehydrodechlorinationrdquo Environmental Science and Technologyvol 39 no 5 pp 1346ndash1353 2005

[408] M O Nutt K N Heck P Alvarez and M S Wong ldquoImprovedPd-on-Au bimetallic nanoparticle catalysts for aqueous-phasetrichloroethene hydrodechlorinationrdquo Applied Catalysis BEnvironmental vol 69 no 1-2 pp 115ndash125 2006

[409] L Espinal S L Suib and J F Rusling ldquoElectrochemical catalysisof styrene epoxidation with films of MnO

2nanoparticles and

H2O2rdquo Journal of the American Chemical Society vol 126 no

24 pp 7676ndash7682 2004[410] J Fei Y Cui X Yan et al ldquoControlled preparation of MnO2

hierarchical hollow nanostructures and their application inwater treatmentrdquo Advanced Materials vol 20 no 3 pp 452ndash456 2008

[411] I Dror D Baram and B Berkowitz ldquoUse of nanosized catalystsfor transformation of chloro-organic pollutantsrdquoEnvironmentalScience and Technology vol 39 no 5 pp 1283ndash1290 2005

[412] S D Kelly K M Kemner G E Fryxell J Liu S V Mattigodand K F Ferris ldquoX-ray-absorption fine-structure spectroscopystudy of the interactions between contaminant tetrahedralanions and self-assembled monolayers on mesoporous sup-portsrdquo Journal of Physical Chemistry B vol 105 no 27 pp 6337ndash6346 2001

[413] G E Fryxell Y Lin S Fiskum et al ldquoActinide sequestrationusing self-assembled monolayers on mesoporous supportsrdquoEnvironmental Science and Technology vol 39 no 5 pp 1324ndash1331 2005

[414] T Schreiber A Weber K Niedergall et al ldquoWater treatment bymolecularly imprinted polymer nanoparticlesrdquo in Proceedingsof the MRS Spring Meeting amp Exhibit pp Q04ndashQ07 April 2009

[415] J Kim and J W Grate ldquoNano-biotechnology in using enzymesfor environmental remediation single-enzyme nanoparticlesrdquoinNanotechnology and the Environment Applications and Impli-cations B Karn T Masciangioli W Zhang V Colvin andP Alivisatos Eds vol 890 pp 220ndash225 American ChemicalSociety Washington DC USA 2004

[416] J Xu L Bachas andD Bhattacharyya ldquoSynthesis of nanostruc-tured bimetallic particles in polyligand-functionalized mem-branes for remediation applicationsrdquo in Nanotechnology Appli-cations for Clean Water N Savage M Diallo J Duncan AStreet and R Sustich Eds chapter 22 pp 311ndash335 WilliamAndrew Boston Mass USA 2009

[417] H Choi E Stathatos and D D Dionysiou ldquoSol-gel preparationof mesoporous photocatalytic TiO

2films and TiO

2Al2O3

composite membranes for environmental applicationsrdquoAppliedCatalysis B Environmental vol 63 no 1-2 pp 60ndash67 2006

[418] L Wu and S M C Ritchie ldquoEnhanced dechlorinationof trichloroethylene by membrane-supported Pd-coated ironnanoparticlesrdquo Environmental Progress vol 27 no 2 pp 218ndash224 2008

[419] H F Lin R Ravikrishna and K T Valsaraj ldquoReusableadsorbents for dilute solution separation 6 Batch and con-tinuous reactors for the adsorption and degradation of 12-dichlorobenzene from dilute wastewater streams using titaniaas a photocatalystrdquo Separation and Purification Technology vol28 no 2 pp 87ndash102 2002

[420] R Molinari L Palmisano E Drioli andM Schiavello ldquoStudieson various reactor configurations for coupling photocatalysisand membrane processes in water purificationrdquo Journal ofMembrane Science vol 206 no 1-2 pp 399ndash415 2002

[421] Y Yang H Zhang P Wang Q Zheng and J Li ldquoThe influenceof nano-sized TiO

2fillers on the morphologies and properties

of PSF UF membranerdquo Journal of Membrane Science vol 288no 1-2 pp 231ndash238 2007

[422] A Rahimpour S S Madaeni A H Taheri and Y Mansour-panah ldquoCoupling TiO

2nanoparticles with UV irradiation for

modification of polyethersulfone ultrafiltration membranesrdquoJournal of Membrane Science vol 313 no 1-2 pp 158ndash169 2008

[423] G Wu S Gan L Cui and Y Xu ldquoPreparation and charac-terization of PESTiO

2composite membranesrdquo Applied Surface

Science vol 254 no 21 pp 7080ndash7086 2008[424] G C C Yang and C-J Li ldquoPreparation of tubular TiO

2Al2O3

composite membranes and their performance in electrofiltra-tion of oxide-CMP wastewaterrdquo Desalination vol 200 no 1ndash3pp 74ndash76 2006

[425] Q Zhang Y Fan and N Xu ldquoEffect of the surface properties onfiltration performance of Al2O3-TiO2 composite membranerdquoSeparation and Purification Technology vol 66 no 2 pp 306ndash312 2009

[426] L Wu M Shamsuzzoha and S M C Ritchie ldquoPreparationof cellulose acetate supported zero-valent iron nanoparticlesfor the dechlorination of trichloroethylene in waterrdquo Journal ofNanoparticle Research vol 7 no 4-5 pp 469ndash476 2005

[427] D E Meyer K Wood L G Bachas and D BhattacharyyaldquoDegradation of chlorinated organics by membrane-immobi-lized nanosized metalsrdquo Environmental Progress vol 23 no 3pp 232ndash242 2004

[428] L Wu and S M C Ritchie ldquoRemoval of trichloroethylenefrom water by cellulose acetate supported bimetallic NiFenanoparticlesrdquo Chemosphere vol 63 no 2 pp 285ndash292 2006

[429] J Xu and D Bhattacharyya ldquoFePd nanoparticle immobiliza-tion in microfiltration membrane pores synthesis characteri-zation and application in the dechlorination of polychlorinatedbiphenylsrdquo Industrial and Engineering Chemistry Research vol46 no 8 pp 2348ndash2359 2007

[430] V V Tarabara ldquoMultifunctional nanomaterial-enabled mem-branes for water treatmentrdquo in Nanotechnology Applications forClean Water N Savage M Diallo J Duncan A Street and RSustich Eds chapter 5 pp 59ndash75 William Andrew BostonMass USA 2009

[431] J Xu and D Bhattacharyya ldquoMembrane-based bimetallicnanoparticles for environmental remediation synthesis andreactive propertiesrdquo Environmental Progress vol 24 no 4 pp358ndash366 2005

[432] K Venkatachalam X Arzuaga N Chopra et al ldquoReductivedechlorination of 331015840441015840-tetrachlorobiphenyl (PCB77) usingpalladium or palladiumiron nanoparticles and assessment ofthe reduction in toxic potency in vascular endothelial cellsrdquoJournal of Hazardous Materials vol 159 no 2-3 pp 483ndash4912008

[433] B S Karnik S H R Davies K C Chen D R JaglowskiM J Baumann and S J Masten ldquoEffects of ozonation on thepermeate flux of nanocrystalline ceramic membranesrdquo WaterResearch vol 39 no 4 pp 728ndash734 2005

[434] HVerweijM C Schillo and J Li ldquoFastmass transport throughcarbon nanotube membranesrdquo Small vol 3 no 12 pp 1996ndash2004 2007


[435] G C C Yang and C-M Tsai ldquoPreparation of carbonfiberscarbonalumina tubular composite membranes and theirapplications in treating Cu-CMPwastewater by a novel electro-chemical processrdquo Journal of Membrane Science vol 321 no 2pp 232ndash239 2008

[436] Y Yao G Li K A Gray and R M Lueptow ldquoSingle-walledcarbon nanotube-facilitated dispersion of particulate TiO

2on

ZrO2ceramic membrane filtersrdquo Langmuir vol 24 no 14 pp

7072ndash7075 2008[437] S Peltier M Cotte D Gatel L Herremans and J Cavard

ldquoNanofiltration improvements of water quality in a large dis-tribution systemrdquoWater Science and Technology Water Supplyvol 3 no 1-2 pp 193ndash200 2003

[438] G L Jadav and P S Singh ldquoSynthesis of novel silica-polyamidenanocomposite membrane with enhanced propertiesrdquo Journalof Membrane Science vol 328 no 1-2 pp 257ndash267 2009

[439] M F Ottaviani P Favuzza M Bigazzi N J Turro S Jockuschand D A Tomalia ldquoA TEM and EPR investigation of thecompetitive binding of uranyl ions to starburst dendrimers andliposomes potential use of dendrimers as uranyl ion spongesrdquoLangmuir vol 16 no 19 pp 7368ndash7372 2000

[440] E R Birnbaum K C Rau and N N Sauer ldquoSelective anionbinding from water using soluble polymersrdquo Separation Scienceand Technology vol 38 no 2 pp 389ndash404 2003

[441] A BottinoGCapannelli VDAsti andP Piaggio ldquoPreparationand properties of novel organic-inorganic porous membranesrdquoSeparation and Purification Technology vol 22-23 pp 269ndash2752001

[442] K Ebert D Fritsch J Koll and C Tjahjawiguna ldquoInfluenceof inorganic fillers on the compaction behaviour of porouspolymer based membranesrdquo Journal of Membrane Science vol233 no 1-2 pp 71ndash78 2004

[443] T-H Bae and T-M Tak ldquoEffect of TiO2nanoparticles on

fouling mitigation of ultrafiltration membranes for activatedsludge filtrationrdquo Journal of Membrane Science vol 249 no 1-2 pp 1ndash8 2005

[444] NMaximous G Nakhla KWong andWWan ldquoOptimizationof Al2O3PES membranes for wastewater filtrationrdquo Separation

and Purification Technology vol 73 no 2 pp 294ndash301 2010[445] M T M Pendergast J M Nygaard A K Ghosh and E M V

Hoek ldquoUsing nanocomposite materials technology to under-stand and control reverse osmosis membrane compactionrdquoDesalination vol 261 no 3 pp 255ndash263 2010

Submit your manuscripts athttpwwwhindawicom

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CorrosionInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Polymer ScienceInternational Journal of



CeramicsJournal of


CompositesJournal of

NanoparticlesJournal of



International Journal of

Biomaterials


NanoscienceJournal of

TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Journal of

NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

CrystallographyJournal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014


CoatingsJournal of

Advances in

Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Smart Materials Research



MetallurgyJournal of


BioMed Research International

MaterialsJournal of


Nano

materials


Journal ofNanomaterials


parts of the world [19] The pressure on freshwater resourcesdue to the increasing worldrsquos demand of food energy andso forth [20 21] is increasing more and more due topopulation growth and threats of climate change Pollutingsurfaceground water sources is another cause of reducedfresh water supplies [22ndash24] Aquifers around the worldare depleting and being polluted due to multiple problemsof saltwater intrusion soil erosion inadequate sanitationcontamination of groundsurface waters by algal bloomsdetergents fertilizers pesticides chemicals heavy metalsand so forth [25ndash28]

The occurrence of newemerging microcontaminants(eg endocrine disrupting compounds (EDCs)) in pol-luted waterwastewater has rendered existing conventionalwaterwastewater treatment plants ineffective to meet theenvironmental standards The discharge of these compoundsinto the aquatic environment has affected all living organ-isms The traditional materials and treatment technologieslike activated carbon oxidation activated sludge nanofil-tration (NF) and reverse osmosis (RO) membranes are noteffective to treat complex and complicated polluted waterscomprising pharmaceuticals personal care products surfac-tants various industrial additives and numerous chemicalspurported The conventional water treatment processes arenot able to address adequately the removal of awide spectrumof toxic chemicals and pathogenic microorganisms in rawwater

This is the right time to address water problems sinceaquifers around the world are depleting due to multiplefactors such as saltwater intrusion and contamination fromsurface waters Using better purification technologies canreduce problems of water shortages health energy andclimate change A considerable saving of potable water canbe achieved through reuse of wastewater which in turnrequires the development materials and methods which areefficient cost-effective and reliable Although dilution ofcomplex wastewater effluents can help decreasing the loadof micropollutants downstream [29 30] however muchof them pass through conventional water treatment dueto occurrence of these substances in micro- or even innanograms per liter

Biological treatment systems such as activated sludgeand biological trickling filters are unable to remove a widerange of emerging contaminants and most of these com-pounds remain soluble in the effluent [31ndash33] Physicochem-ical treatments such as coagulation flocculation or limesoftening proved to be ineffective for removing differentEDCs and pharmaceutical compounds in various studies[34ndash36] Chlorination though providing residual protectionagainst regrowth of bacteria and pathogens [37 38] results inundesirable tastes and odors [39] in addition to the formingof different disinfection by-products (DBPs) in portabledrinking water [40ndash43] Ozonation has been considered to bea less attractive alternative due to expensive costs and shortlifetime Both ultraviolet (UV) photolysis and ion exchangethough being advanced type of treatments are not feasiblealternatives for micropollutants removal [44]

Membrane processes like microfiltration ultrafiltrationNF and RO which are pressure-driven filtration processes

are considered as some new highly effective processes[44ndash49] These are considered as alternative methods ofremoving huge amounts of organic micropollutants [50ndash52] Waterwastewater treatment by membrane techniquesis cost-effective and technically feasible and can be betteralternatives for the traditional treatment systems since theirhigh efficiency in removal of pollutants meets the highenvironmental standards [53] NF and RO have proved to bequite effective filtration technologies for removal of microp-ollutants [54 55] RO is relatively more effective than NF buthigher energy consumption in RO makes it less attractivethan NF where removal of pollutants is caused by differentmechanisms including convection diffusion (sieving) andcharge effects [56] Although NF based membrane processesare quite effective in removing huge loads of micropollutants[57] advancedmaterials and treatmentmethods are requiredto treat newly emerging micropollutants

Since the water industry is required to produce drinkingwater of high quality there is a clear need for the devel-opment of cost-effective and stable materials and methodsto address the challenges of providing the fresh water inadequate amounts There are inventions of new treatmentmethods however they need to be stable economical andmore effective as compared with the already existing tech-niques For this traditional treatment technologies have tobe modernized that is updated or modified or replacedby developing materials and methods which are efficientcost-effective and reliable This is particularly important toachieve a considerable potable water savings through reuse ofwastewater in addition to tackling the day-by-day worseningquality of drinking water

Nanotechnology has been considered effective in solvingwater problems related to quality and quantity [58] Nanoma-terials (eg carbon nanotubes (CNTs) and dendrimers) arecontributing to the development of more efficient treatmentprocesses among the advanced water systems [59] Thereare many aspects of nanotechnology to address the multipleproblems of water quality in order to ensure the environmen-tal stabilityThis study provides a unique perspective on basicresearch of nanotechnology for waterwastewater treatmentand reuse by focusing on challenges of future research

The paper has three main sections following the intro-duction which briefly discusses the traditional and currentpractices in waterwastewater treatment Section 2 describesmainly the properties and types of nanomaterials and theirimportance in waterwastewater treatment Section 3 dis-cusses different types of nanomaterials focusing on mem-branes for treating a variety of pollutants inwaterwastewaterThe application of nanomaterials is reviewed based on theirfunctions in unit operation processes Section 4 providesa summary and outlook in the form of conclusions andrecommendations for their full-scale application

2 Nanotechnology forWaterWastewater Purification

There are rising demands of clean water throughout theworld as freshwater sourcesresources are depleting due to















2photocatalysts




10minus1 1 10 10

310

210

410

510

610

710

8


(nm)






















2having good pho-





2


2 that is only




















2






2thin films













2nanofibers







3O4) Ag and Fe

3O4







2Al2O3(alu-








2) have also been









2


2




2O3and







2



2are























2nanoparticles




2O3were used



4







2O3nanoparticles










2or modified nano-








2O3substrate showed



2O3


2and Fe






2



2O3nanoparticles

















Treated water





Acknowledgment


References









































































































2nanoparticle























































2O3



























2














2films








2













2rdquo



2active


























































2nanoparticle self-











































































































































































2














2nanocrystals under






2particlesrdquo





2























































2nanoparticles and











2films and TiO

2Al2O3














2Al2O3















2on





















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials

















2photocatalysts




10minus1 1 10 10

310

210

410

510

610

710

8


(nm)






















2having good pho-





2


2 that is only




















2






2thin films













2nanofibers







3O4) Ag and Fe

3O4







2Al2O3(alu-








2) have also been









2


2




2O3and







2



2are























2nanoparticles




2O3were used



4







2O3nanoparticles










2or modified nano-








2O3substrate showed



2O3


2and Fe






2



2O3nanoparticles

















Treated water





Acknowledgment


References









































































































2nanoparticle























































2O3



























2














2films








2













2rdquo



2active


























































2nanoparticle self-











































































































































































2














2nanocrystals under






2particlesrdquo





2























































2nanoparticles and











2films and TiO

2Al2O3














2Al2O3















2on





















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials





10minus1 1 10 10

310

210

410

510

610

710

8


(nm)






















2having good pho-





2


2 that is only




















2






2thin films













2nanofibers







3O4) Ag and Fe

3O4







2Al2O3(alu-








2) have also been









2


2




2O3and







2



2are























2nanoparticles




2O3were used



4







2O3nanoparticles










2or modified nano-








2O3substrate showed



2O3


2and Fe






2



2O3nanoparticles

















Treated water





Acknowledgment


References









































































































2nanoparticle























































2O3



























2














2films








2













2rdquo



2active


























































2nanoparticle self-











































































































































































2














2nanocrystals under






2particlesrdquo





2























































2nanoparticles and











2films and TiO

2Al2O3














2Al2O3















2on





















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials











2having good pho-





2


2 that is only




















2






2thin films













2nanofibers







3O4) Ag and Fe

3O4







2Al2O3(alu-








2) have also been









2


2




2O3and







2



2are























2nanoparticles




2O3were used



4







2O3nanoparticles










2or modified nano-








2O3substrate showed



2O3


2and Fe






2



2O3nanoparticles

















Treated water





Acknowledgment


References









































































































2nanoparticle























































2O3



























2














2films








2













2rdquo



2active


























































2nanoparticle self-











































































































































































2














2nanocrystals under






2particlesrdquo





2























































2nanoparticles and











2films and TiO

2Al2O3














2Al2O3















2on





















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials











2






2thin films













2nanofibers







3O4) Ag and Fe

3O4







2Al2O3(alu-








2) have also been









2


2




2O3and







2



2are























2nanoparticles




2O3were used



4







2O3nanoparticles










2or modified nano-








2O3substrate showed



2O3


2and Fe






2



2O3nanoparticles

















Treated water





Acknowledgment


References









































































































2nanoparticle























































2O3



























2














2films








2













2rdquo



2active


























































2nanoparticle self-











































































































































































2














2nanocrystals under






2particlesrdquo





2























































2nanoparticles and











2films and TiO

2Al2O3














2Al2O3















2on





















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials









2) have also been









2


2




2O3and







2



2are























2nanoparticles




2O3were used



4







2O3nanoparticles










2or modified nano-








2O3substrate showed



2O3


2and Fe






2



2O3nanoparticles

















Treated water





Acknowledgment


References









































































































2nanoparticle























































2O3



























2














2films








2













2rdquo



2active


























































2nanoparticle self-











































































































































































2














2nanocrystals under






2particlesrdquo





2























































2nanoparticles and











2films and TiO

2Al2O3














2Al2O3















2on





















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials






















2nanoparticles




2O3were used



4







2O3nanoparticles










2or modified nano-








2O3substrate showed



2O3


2and Fe






2



2O3nanoparticles

















Treated water





Acknowledgment


References









































































































2nanoparticle























































2O3



























2














2films








2













2rdquo



2active


























































2nanoparticle self-











































































































































































2














2nanocrystals under






2particlesrdquo





2























































2nanoparticles and











2films and TiO

2Al2O3














2Al2O3















2on





















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials






2or modified nano-








2O3substrate showed



2O3


2and Fe






2



2O3nanoparticles

















Treated water





Acknowledgment


References









































































































2nanoparticle























































2O3



























2














2films








2













2rdquo



2active


























































2nanoparticle self-











































































































































































2














2nanocrystals under






2particlesrdquo





2























































2nanoparticles and











2films and TiO

2Al2O3














2Al2O3















2on





















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials








Treated water





Acknowledgment


References









































































































2nanoparticle























































2O3



























2














2films








2













2rdquo



2active


























































2nanoparticle self-











































































































































































2














2nanocrystals under






2particlesrdquo





2























































2nanoparticles and











2films and TiO

2Al2O3














2Al2O3















2on





















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials



















































































2nanoparticle























































2O3



























2














2films








2













2rdquo



2active


























































2nanoparticle self-











































































































































































2














2nanocrystals under






2particlesrdquo





2























































2nanoparticles and











2films and TiO

2Al2O3














2Al2O3















2on





















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




























2O3



























2














2films








2













2rdquo



2active


























































2nanoparticle self-











































































































































































2














2nanocrystals under






2particlesrdquo





2























































2nanoparticles and











2films and TiO

2Al2O3














2Al2O3















2on





















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials


















2














2films








2













2rdquo



2active


























































2nanoparticle self-











































































































































































2














2nanocrystals under






2particlesrdquo





2























































2nanoparticles and











2films and TiO

2Al2O3














2Al2O3















2on





















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials
















































2nanoparticle self-











































































































































































2














2nanocrystals under






2particlesrdquo





2























































2nanoparticles and











2films and TiO

2Al2O3














2Al2O3















2on





















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials

































































































































































2














2nanocrystals under






2particlesrdquo





2























































2nanoparticles and











2films and TiO

2Al2O3














2Al2O3















2on





















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials



















































2nanoparticles and











2films and TiO

2Al2O3














2Al2O3















2on





















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials






2on





















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials










CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials



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