research article a novel photocatalyst with ferromagnetic...

Hindawi Publishing CorporationThe Scientific World JournalVolume 2013 Article ID 196470 9 pageshttpdxdoiorg1011552013196470

Research ArticleA Novel Photocatalyst with Ferromagnetic Core Used forthe Treatment of Olive Oil Mill Effluents from Two-PhaseProduction Process

Javier Miguel Ochando-Pulido1 Gassan Hodaifa2

Mariacutea Dolores Viacutector-Ortega1 and Antonio Martiacutenez-Ferez1

1 Chemical Engineering Department University of Granada 18071 Granada Spain2Molecular Biology and Biochemical Engineering Department University Pablo de Olavide 14013 Seville Spain

Correspondence should be addressed to Gassan Hodaifa ghodaifaupoes

Received 26 August 2013 Accepted 2 October 2013

Academic Editors F Oktar and Z Zhang

Copyright copy 2013 Javier Miguel Ochando-Pulido et al This is an open access article distributed under the Creative CommonsAttribution License which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited

Photocatalytic degradation of olive oil mill wastewater from two-phase continuous centrifugation process was studied A novelphotocatalyst with ferromagnetic properties was characterized and investigated The degradation capacity of the photocatalyticprocess of olive oil washing wastewater (OMW) and mixture of olives and olive oil (1 vv) washing wastewaters (MOMW) wasdemonstrated At lab-scale the COD removal and residence time (120591) for MOMW and OMW were 584 (120591 = 2 h) and 214(120591 = 3 h) respectively On the other hand at pilot scale 234 CODremoval 192 total phenolsremoval and 281 total suspendedsolidsremoval were registered at the end of the UVTiO2 process for OMW whereas 583 CODremoval 275 total phenolsremoval and250 total suspended solidsremoval for MOMW Also before the UVTiO

2reaction a pH-T flocculation operation as pretreatment

was realized The overall efficiency of the treatment process for MOMW was up to 91 of CODremoval in contrast with 332 ofCODremoval for OMW

1 Introduction

Photocatalysis with titaniumdioxide (TiO2) under ultraviolet

light (UV) is an advanced oxidation process (AOP) in whichthe titanium dioxide semiconductor absorbs UV radiationand generates hydroxyl radicals (OH∙) In detail conductionband electrons and valence band holes of TiO

2are initially

yielded by UV irradiation Thereafter band electrons arecapable of interacting with surface-adsorbed molecular oxy-gen to form superoxide radical anions (O

2

∙) whereas bandholes will interact with water to produce hydroxyl radicals(OH∙) (Figure 1) [1] Organic compounds can undergooxidative degradation through their reactions with valenceband holes hydroxyl (OH∙) and superoxide (O

2

∙) radicalsas well as reductive cleavage through their reactions withelectrons (eminus)

The titaniumdioxidemolecule absorbs nearUV radiation(wavelength 120582 lt 400 nm) leading to the generation of

electronvalence band holes pairs as indicated as follows(Figure 1)

TiO2(ℎ sdot V) 997888rarr TiO

2(eminus + h+) (1)

Valence band holes are prone to react with absorbed sub-stances in particular with water molecules (H

2Oad) (2) or

hydroxyl ions (OHminusad) (3) generating hydroxyl radicals(OH∙) as follows

TiO2(h+) +H

2Oad 997888rarr TiO

2+OH∙ +H+ (2)

TiO2(h+) +OHminusad 997888rarr TiO

2+OH∙ (3)

Absorbed oxygen is the main electron acceptor species asfollows

TiO2(eminus) +O

2997888rarr TiO

2+O2

∙ (4)

Among the known semiconductor photocatalysts (ZnOWO3 CdS ZnS SrTiO

3 SnO

2 Fe2O3) TiO

2has deserved

2 The Scientific World Journal

Electron energy

E

UV-irradiation120582 lt 400nm

Conduction band

Valence band

Recombination of charges

32 eV

eminus

h+

Semiconductor (TiO2)

Adsorption (O2)

Oxidation (H+ + OH∙)Adsorption (H2O)

Adsorption(Pollutant P)

Deg

rada

tion

Reduction (O∙minus2 )

Pollutant P∙

Oxidation (P∙+)

Figure 1 Activation of the TiO2nanocatalyst by UV light

particular interest owed to its high oxidizing power of organiccontaminants along with its chemical stability and low cost[2] The key advantages of TiO

2UV light photocatalysis

process rely on the very high volume to surface ratio oftitania nanoparticles that lead to the absence of mass transferlimitationswhen nanoparticles are used as photocatalysts thepossibility of being triggered at ambient operating conditionsand to exploit sunlight instead of electric illumination incase of doped TiO

2 and the fact that TiO

2is a highly

active and nontoxic molecule capable of achieving completemineralization of a wide range of organic pollutants oroxidizing them into harmless compounds [3 4]

Olive oil factories commonly known as olive millsgenerate as by-product effluents (OME) an average dailyamount of 1m3 of wastewater derived from thewashing of theolives (oliveswashingwastewater OWW) togetherwithmorethan 10m3 of wastewater coming from the centrifugationprocess used for the extraction of the olive oil (olive oil millwastewater OMW) OMW exhibits a series of characteristicsthatmake their reclamation by conventional physicochemicaltreatments extremely difficult The presence of phytotoxicrefractory pollutants such as phenolic compounds organicacids tannins long chain fatty acids and organohalogenatedcontaminants makes these effluents recalcitrant to biologicaldegradation and thus inhibits the efficiency of biologicalprocesses Moreover the physicochemical composition ofOMW is extremely variable as it depends on several factorssuch as the extraction process edaphoclimatic and cultiva-tion parameters as well as the type quality and maturityof the olives [5ndash7] OMW typically exhibit strong odornuisance acid pH intensive violet-dark color considerablesaline toxicity reflected by high electroconductivity (EC)values and very heavy organic pollutants load [5] Additionaldifficulties such as small size and geographical dispersion ofolive oil mills as well as seasonality of olive oil production arefaced in the management of these agroindustry effluents

In this research work the treatment of the effluentsgenerated by olive mills working with the two-phase oliveoil extraction process (OMW-2) by TiO

2UV light photo-

catalysis is addressed The aforementioned set of featureshighlight TiO

2UV light photocatalysis as a potential AOP

from a technical and economical point of view if comparedwith other AOPs for the treatment of industrial effluentspresenting high organic matter (COD) pollutants load [8ndash20] However the main handicap in applying photocatalyticprocesses for the reclamation of industrial and agrofoodeffluents relies in the cost of the catalyst In this sensethe difficulty in recovering the catalyst poses the maintechnical-economical drawback To solve this problem anovel photocatalyst with ferromagnetic properties for ease ofrecovery and high effectiveness in the treatment of OMW-2 was developed Also the evolution of the organic matter(COD) and degradation rates were determined

2 Experimental

21 Feedstocks Olive Oil Washing Wastewater (OMW)and Mixture of Olives and Olive Oil Washing Wastewater(MOMW) Samples of OWW from the washing machinesand OMW at the outlet of the vertical centrifuges weretaken from an olive oil mill located in Jaen (Spain) operatingwith the modern two-phase olive oil extraction procedure[5] Two different raw feedstocks were used for the presentinvestigation on one hand OMW and on the other a 1 1(vv) mixture of olives and olive oil washing wastewater(MOMW) The physicochemical characteristics of both rawfeedstocks are reported in Table 1

As it can be noted the organic load in the effluent fromthe vertical centrifugation (OMW) is much higher than thatfrom the washing of the olives (OWW) andMOMW and thesame occurs for the concentration of phenolic compounds

The Scientific World Journal 3

Table 1 Raw OMW and MOMW physicochemical composition

Parameters OMW MOMWpH 49ndash51 59ndash63Electric conductivity mS cmminus1 176ndash184 142ndash154Total suspended solids g Lminus1 31ndash58 61ndash69COD g Lminus1 164ndash166 41ndash42Total phenols g Lminus1 0181ndash0184 0082ndash0087

(Table 1) This is explained on the basis that organic pollu-tants and particularly phenolic compounds are transferredfrom the oil phase to the water (hydrophilic phase) duringthe vertical centrifugation whereas during the olives washingprocess the level of organic contamination attained in thewater (OWW) is much lower and phenolic species arenegligible only measured in case of fruit rupture in therecollection of the fruit or during the washing procedure[6] The organic load in OWW stands normally below thelimits for discharge on superficial suitable terrains Howeverconcentration values may exceed the established standards(Guadalquivir Hydrographical Confederation 2006 COD lt1000mg O

2Lminus1) depending mainly on the water flowrate

employed in the olives washing machines during the fruitcleaning procedure

22 Pretreatment of the RawOMWandMOMWEffluents Infirst place both raw feedstocks were subjected to gridding(cut-size equal to 300 120583m) with the primary objective ofremoving coarse particles After this a pretreatment pro-cedure based on pH-temperature flocculation studied inprevious works [21] was applied to the OMW and MOMWeffluents In this study pH-T flocculation process optimiza-tion was checked again at lab scale on the target feedstocksand finally conducted on a pilot scale

Laboratory scale experiments were first carried out inorder to find the best pH and temperature conditions for theflocculation process OMW and MOMW samples (200mL)were poured in beakers (05 L) fitted with magnetic stirringExperiments at different pH values (ranging from 2 up to7) and several temperature values (15 25 and 50∘C) wereperformed HNO

3(70ww) and NaOH (1N) were used to

reduce or increase the pHvalues of the feedstock respectivelyFor all experiments the same procedurewas adopted a shortinitial high stirring rate mixing (90 s 1000 rpm) followedby slow stirring for a longer amount of time (20min320 rpm) The initial strong mixing stage promotes uniformdispersion of the flocculant and particles collisions whereasthe following weak mixing ensures ideal conditions for themovement of the flocks in suspension without destroyingthem After that mixing was completely stopped the samplewas left to settle for 24 hours and the mud was extractedfrom the bottom of the reactor and finally dried in order tocalculate the sludge fraction and the fraction of clarifiedwater(vv) Additionally total suspended solids (TSS) removalefficiencywasmeasured in the clarified supernatant at the endof each experiment

Once optimized the pH-Tflocculation processwas scaledup and conducted in a stirred batch reactor (20 L) providedwith a turbine impeller stirrer and the achieved reduction oftotal phenols concentration (TPh) chemical oxygen demand(COD) and total suspended solids (TSS) were finally mea-sured

23 Lab-Made Production of the Ferromagnetic-CoreNanocat-alyst The possibilities of application of TiO

2are being

investigated since the early 1970s after a pioneering work byFujishima andHonda [22] and is nowadays a well-known andcommercially used photocatalyst [23] Nanocrystalline TiO

2

immobilized on supporting materials such as glass sandor zeolite can improve the separation efficiency Magneticseparation provides a very convenient approach for remov-ing and recycling magnetic particles (such as magnetiteferrite and barium ferrite) by applying external magneticfields The incorporation of magnetic components into TiO

2

nanoparticle-based catalysts may therefore enhance the sep-aration and recovery of nanosized TiO

2[24] Very recently

a large-scale synthesis of discrete and uniformly sized superparamagnetic Fe

3O4SiO2was developed [25] Reaction time

tetraethyl-orthosilicate (TEOS)Fe3O4ratio and hydrophilic

Fe3O4seeds concentration were found to be very important

parameters in the control of silica shell thickness from125 nm to 45 nm [26]

However currently there is little literature on the syn-thesis of Fe

3O4SiO2TiO2core-shell nanoparticles and their

photocatalytic properties Gad-Allah et al [27] reported thepreparation of Fe

3O4SiO2TiO2nanocomposites However

Fe3O4SiO2TiO2core-shell nanoparticleswere in the formof

patches and not discrete nanoparticles thus these nanopar-ticles exhibited reduction of their surface area and photocat-alytic properties Abramson et al [28] produced core-shell-shell Fe

3O4SiO2TiO2nanoparticles of few tens nanometers

by successively coating onto the magnetic nanoparticles aSiO2layer and a TiO

2layer using sol-gel methods

In this work the production process of the photocatalystwas performed in three subsequent steps Firstly magnetitewas produced by using a spinning disk reactor (SDR)This technology allows obtaining nanomaterial by chemicalprecipitation or sol-gel processes continuously Two reactantswere used on the one side an aqueous solution of FeCl

3 HCl

and Na2SO3and on the other side an aqueous solution of

NH4OHAs pointed out previously byDeCaprariis et al [29]

the location of the feed points over the disk influences theprecipitation outcome In this case the first reactant was fedat the center of the disk whereas the second one was injectedat 2 cm of distance This permits producing magnetite witha modal particle size of 30 nm A scheme of the adoptedspinning disk reactor is shown in Figure 2

The second step consists of a coating of silica performedby adding the dried magnetite particles to a TEOS-ethanol-NH3solution The coated particles were then recovered back

by magnets gently dried at 80∘C and calcinated at 450∘CFinally the TiO

2coating was performed by pouring

the silica-coated particles in a titanium tetraisopropoxide-ethanol solution and adding H

2O2dropwise to the solution


Liquid feed

Transparenttop cover

Water cooled

wall

Product

Heater

Spinning DISC

Figure 2 Scheme of the adopted rotating disk reactor [21 29]

under strong mixing conditions Again the recovered parti-cles were dried gently at 80∘C and a final calcination at 450∘Cwas performed

24 Characterization of the Lab-Made Photocatalyst Parti-cle size distribution (PSD) analysis was performed with adynamic light scattering device (Plus90 nanosizer) suppliedby Brookhaven Determination of the presence of siliconand titanium atoms was conducted by means of an energy-dispersive X-ray diffraction (EDX) analysis Transmissionelectron microscopy (TEM) was carried out with an AurigaZeiss instrument to observe the overall morphology of thenanoparticles

25 TiO2UV Photocatalytic Degradation of OMW and

OWMW TiO2UV photocatalysis process was firstly opti-

mized at lab scale on 200mL samples of the supernatant ofOMW and OWMW previously pretreated by pH-T floccula-tion Lab experiments were conducted in 05 L beakers withmagnetic stirring at ambient temperature (20 plusmn 05∘C) andmedium agitation speed (500 rpm) during 2ndash4 hours underirradiation of an UV lamp (nominal power 45W wavelength365 nm) The performance of the lab-made ferromagnetic-core photocatalytic nanoparticles was contrasted with thatof commercial TiO

2P-25 catalyst provided by Degussa for

comparison purposes Different catalysts dosages (05 1 3and 9 g Lminus1 for both catalysts plus 20 g Lminus1 for the commercialDegussa P-25) were tested and reduction of the COD valueswas followed during the course of the experiments Labora-tory scale experiments aimed to find the best TiO

2catalyst

and its optimal initial dosageOnce lab-scale optimization was accomplished the pho-

tocatalysis processwas carried out in an agitated batch reactor(8 L) provided with an UV lamp on top and a turbineimpeller stirrer Achieved reduction of COD total phenols(TPh) concentration and total suspended solids (TSS) werechecked at the end of the pilot scale process

26 Analytical Methods Chemical oxygen demand (COD)total phenols (TPh) total suspended solids (TSS) electrocon-ductivity (EC) and pH were measured following standard

methods (Greenberg 1992) All analytical methods wereapplied in triplicate with analytical-grade reagents including70 (ww) HNO

3 98 (ww) NaOH 98 (ww) Na

2SO3

30 (ww) NH4OH 37 (ww) HCl and 30 (ww) FeCl

3

supplied by Panreac

3 Results and Discussion

31 Pretreatment of OMW by pH-T Flocculation Figure 3shows the optimal operating conditions found at lab scalefor the pH-T flocculation process taking TSS reduction insupernatant as key parameter suggested working at temper-atures of 25 plusmn 05∘C and pH values equal to 25 plusmn 025 (byadding 055 plusmn 005 vv 70 HNO

3) OMW is considered

to be closely related to humic compounds because it is darkcolored contains phenols and shares some of the propertiesof humic substances Jin et al [30] studies on particle sizedistribution (PSD) of humic acid by dynamic light scatteringconfirmed higher hydrodynamic diameters at lower temper-ature values predominantly in form of submicron aggregatesand a small fraction of supramicron aggregates due to minorsolubility of the organic matter Furthermore at low pHvalues (pH lt 4) these macromolecules are protonated andthus neutrally chargedThe absence of electrostatic repulsionamong the humic macromolecules thus enhances molecularaggregation Similar trends with regard to natural organicmatter (NOM) macromolecules were observed by Hong andElimelech [31]

Upon those operating conditions the final reductionvalues achieved at the end of the pilot scale pH-T flocculationprocess were equal to 725 TSS 126 COD and 50 TPhwith a recovery of up to 875 vv of the clarified water whichmeans a resultant 125 vv of sludge In a similar way forthe MOMW effluent these results were equal to 934 TSS143 COD and 52 TPh reduction efficiencies In this casea final recovery of up to 902 vv of the clarified supernatantwas accomplished that is leading to a resultant 98 vvof sludge The pH-T coagulation-flocculation process seemsto be a cost-effective pretreatment for the removal of theTSS concentration from OMW and MOMW particularly ifcompared to current coagulation-flocculation processes with


35

30

25

20

15

10

05

00

0 20 40 60

pH = 2

pH = 25

pH = 3

pH = 35

pH = 6

pH = 65pH = 7

TSS

in su

pern

atan

t (g L

minus1)

040

035

030

025

020

015

010

000

pH = 2

pH = 25

pH = 35

pH = 6

pH = 7

TSS

in su

pern

atan

t (g L

minus1)

005

0 20 40 60

T (∘C) T (∘C)

Figure 3 Lab-scale results of pH-T flocculation process on OMW (left caption) and MOMW (right capt)

Figure 4 Photography of the ferromagnetic photocatalytic nano-particles

commercial flocculants which may lead in our experience tolower efficiency values at higher costs

32 Characterization of the Lab-Made Photocatalyst Thelab-made nanocatalyst (Figure 4) is internally composedof a ferromagnetic core (120574-Fe

2O3 modal particle size of

30 nm) on which two subsequent layers of silica and titaniaare attached (120574 Fe

2O3SiO2TiO2) Energy-dispersive X-ray

diffraction spectrum (EDX) of the ferromagnetic nanopar-ticles is given in Figure 5 whereas transmission electronmicroscopy (TEM) microphotographs and particle size dis-tribution (PSD) analysis of the obtained ferromagnetic-corenanoparticles are shown in Figure 6 TEM image of thenanoparticles shows regular overall morphology The finalmean particle size of the nanopowder was equal to 79 nmwith very uniform homogeneous and pure anatase TiO

2

phase (100) with some traces of brookite EDX analysisperformed to determine the elemental composition of theobtained composite nanoparticles shows that the obtainednanopowder consisted of Fe Si and Ti verifying the presenceof both silica and TiO

2layers

33 Photocatalytic Degradation of OMW The evolution ofthe organic matter (COD) removal from OMW during thelab-scale UVTiO

2process with both catalysts and feedstocks

is reported in Figure 7 A semilogarithmic fitting curvewas applied for interpolating the COD reduction duringoperation time as follows

ΔCOD = 119861 sdot ln (119905) + ΔCOD (05) (5)

where 119861 (g Lminus1 hminus1) indicates the rate of degradation of theorganic matter during the photocatalysis experiments andΔCOD (05) (g Lminus1) makes reference to the initial abatementof organic pollutantsOverall results of the lab-scaleUVTiO

2

tests are reported in Table 2The laboratory-made ferromagnetic-core photocatalyst

was found to provide slightly higher COD removal than thecommercial one for both feedstocks upon lower initial cata-lyst dosages equal to 1 g Lminus1 and 05 g Lminus1 for the treatmentof OMW and MOMW respectively This is supported bythe 100 anatase TiO

2phase of the lab-made ferromagnetic

catalyst Among the three crystalline phases of TiO2 called

anatase rutile and brookite the former is the most activeunder UV irradiation strongly dependent on the particle sizeand habit too [32]The sol-gel process performed in this workfor the fabrication of the ferromagnetic core catalyst leadsto the formation of homogeneous pure and very uniformparticles (Figure 6(b)) [29]Mixed-phase submicron particlessuch as commercial Degussa P-25 consisting of 70 anataseand 30 rutile seem to provide less effective catalytic action


Cps (

eV)

120574-Fe2O3core

120574-Fe2O3SiO2core-shell

120574-Fe2O3SiO2TiO2core-shell-shell

2 3 4 5 6 7 8 9 101

00

05

10

15

20

25

30

TiCO Si Ti

FeFe

(keV)

Figure 5 Energy-dispersive X-ray diffraction spectrum (EDX) of the ferromagnetic nanoparticles

100

75

50

25

0

500 50000

Diameter (nm)

Num

ber

Rel Num = 10000 Cum Num = 6415 Diam (nm) = 7929

(a) (b)

Figure 6 Particle size distribution measured by the nanosizer (a) and TEM photograph (b) of the final ferromagnetic catalyst particles

Moreover significantly higher organic matter removalefficiency was observed for theMOMWeffluent than that forOMWupon the optimal catalyst dosage 584 for the formerin contrast with 214 for the latter (Table 2) Also addinglarge quantities of titania to the wastewater leads to poorerresults Both effects are narrowly connected to hindranceto deep penetration of UV light as a result of the opacityof the solutions due to the major organic pollutants loador to the excessive nanocatalyst concentration respectivelywhich in turn impedes efficient activation of the catalyst Aguided focus on Figure 7 permits to notice that no significantincrease of the COD removal efficiencies was observedbeyond a residence time (120591) of 3 hours for OMW whereaslower residence time was needed in the case of MOMW 120591 =2 h

Finally UVTiO2photocatalysis process was scaled-

up The physicochemical composition of both OMW and

MOMW exiting each pilot scale treatment stage is given inTable 3 By adopting the optimal conditions at pilot scale234 COD 192 TPh and 281 TSS were efficientlyremoved at the end of UVTiO

2process for OMW whereas

583 COD 275 TPh and 250 TSS for MOMWAgain at lab scale not only sensibly higher COD removal

efficiency was noted (234 versus 583) but also phe-nolic compounds (TPh) abatement (192 versus 275)for MOMW if compared with OMW upon the optimizedoperating conditions due to more efficient activation of thenanocatalyst owed to deeper penetration of UV light in lessopaque medium

The novel prepared lab-made titania ferromagnetic-corephotocatalyst (120574-Fe

2O3SiO2TiO2) was developed with the

goal of being able to be whether recovered back from thewastewater stream by a magnetic trap and reused or evenfixed to the photocatalysis reactor giving a solution to the


0

5

10

15

20

25

0 50 100 150 200 250 3000

5

10

15

20

25

0 50 100 150 200 250 300

0

10

20

30

40

50

60

70

0 50 100 150 200 250 3000

10

20

30

40

50

60

70

0 50 100 150 200 250 300

(a998400) (b998400)

(a) (b)

minusΔ

COD

()

t (min)

minusΔ

COD

()

t (min)

minusΔ

COD

()

minusΔ

COD

()

t (min) t (min)

Figure 7 Results withdrawn from UVTiO2photocatalysis experiments on lab scale with OMW commercial Degussa P-25 (a) ◻ = 1 gL loz

= 3 gL Δ = 9 gL x = 20 gL lab-made ferromagnetic-core nanopowder (b) ◼ = 1 gL Q = 3 gL 998771 = 9 gL MOMW Degussa P-25 (a1015840) ◻ =1 gL loz = 3 gL Δ = 9 gL lab-made ferromagnetic-core nanopowder (b1015840) ◼ = 05 gL Q = 1 gL 998771 = 3 gL

Table 2 COD reduction in OMW and MOMW after lab-scale UVTiO2 photocatalysis

Raw effluent Catalyst type Catalyst dosageg Lminus1

CODfinalg Lminus1

minusΔCOD4h

ΔCOD (05)g Lminus1

Bg Lminus1 hminus1

OMW (CODinitial 145 gL)

Degussa P-25

1 121 165 13 263 118 186 25 299 115 207 28 3320 118 186 27 30

Ferromag TiO2

1 114 214 25 323 125 133 16 229 131 103 06 16

MOMW (CODinitial 36 gL)

Degussa P-251 17 543 101 923 16 565 100 939 15 570 101 95

Ferromag TiO2

05 15 584 98 931 16 557 100 913 17 527 99 87


Table 3 Physicochemical composition of OMW andMOMW afterflocculation (F) and photocatalytic (PC) degradation on pilot scale

Feedstock OMW-F OMW-Fand PC MOMW-F MOMW-F

and PCpH 25 29 25 31EC mS cmminus1 17 18 15 15TSS g Lminus1 16 12 04 03COD g Lminus1 145 111 36 15TPh mg Lminus1 172 139 825 598

problem of the recovery of the catalyst and thus considerablyenhancing the cost-effectiveness of the olive mill effluentsreclamation process

Furthermore the overall efficiency of the process bytreating the mixture of the OMW stream mixed with theOWW effluent (MOMW) triggers up to 910 of CODremoval leading to final COD values in the treated waterbelow 15 g Lminus1 in contrast with the barely 332 CODremoval efficiency achieved for the treatment of the OMWseparately

4 Conclusions

According to the results obtained in this investigation thephotocatalytic degradation process is an alternative with highpossibility to be used in the treatment of OMW from two-phase continuous centrifugation process The easy recoveryand reuse of photocatalyst minimizes the operating costsof the treatment process The novel photocatalyst used inthis work offers good results in comparison with othercommercial catalysts as Degussa P-25The photodegradationprocess implies high reduction of the percentages of CODtotal phenols and total suspended solids At pilot scale234 CODremoval 192 total phenolsremoval and 281 totalsuspended solidsremoval were registered at the end of theUVTiO

2process for OMW upon a residence time (120591)

equal to 3 hours whereas 583 CODremoval 275 totalphenolsremoval and 250 total suspended solidsremoval forMOMW upon 120591 = 2 h Also before the UVTiO

2reaction

a pH-T flocculation operation as a pretreatment was realizedThe overall efficiency of the treatment process for MOMWwas up to 91 of CODremoval in contrast with 332 ofCODremoval for OMW

Conflict of Interests

The authors declare that they have no conflict of interests

Acknowledgments

Funding by the European project PHOTOMEM (Contractno FP7-SME-2011 Grant 262470) and the European projectETOILE (Contract no FP7-SME-2007-1 Grant 222331) isacknowledged The Spanish Ministry of Science and Inno-vation is also gratefully acknowledged for having funded theProjects CTQ2007-66178 and CTQ2010-21411

References

[1] J C Crittenden R R Trussell D W Hand K J Howe and GTchobanoglous Water Treatment Principles and Design JohnWiley amp Sons Hoboken NJ USA 2nd edition 2005

[2] S Tieng A Kanaev andK Chhor ldquoNewhomogeneously dopedFe(III)ndashTiO

2photocatalyst for gaseous pollutant degradationrdquo

Applied Catalysis A vol 399 no 1-2 pp 191ndash197 2011[3] D Chen Z Jiang J Geng Q Wang and D Yang ldquoCarbon and

nitrogen co-doped TiO2with enhanced visible-light photocat-

alytic activityrdquo Industrial and Engineering Chemistry Researchvol 46 no 9 pp 2741ndash2746 2007

[4] D Chatterjee and S Dasgupta ldquoVisible light induced photocat-alytic degradation of organic pollutantsrdquo Journal of Photochem-istry and Photobiology C vol 6 no 2-3 pp 186ndash205 2005

[5] L M Nieto G Hodaifa S Rodrıguez J A Gimenezand J Ochando ldquoDegradation of organic matter in olive-oilmill wastewater through homogeneous Fenton-like reactionrdquoChemical Engineering Journal vol 173 no 2 pp 503ndash510 2011

[6] G Hodaifa M E Martınez and S Sanchez ldquoUse of industrialwastewater from olive-oil extraction for biomass production ofScenedesmus obliquusrdquoBioresource Technology vol 99 no 5 pp1111ndash1117 2008

[7] M Niaounakis and C P Halvadakis Olive Processing WasteManagement Literature Review and Patent Survey vol 5 ofWaste Management Series Elsevier Amsterdam The Nether-lands 2nd edition 2006

[8] H Inan A Dimoglo H Simsek and M Karpuzcu ldquoOlive oilmill wastewater treatment by means of electro-coagulationrdquoSeparation and Purification Technology vol 36 no 1 pp 23ndash312004

[9] U T Un S Ugur A S Koparal and U B OgutverenldquoElectrocoagulation of olive mill wastewatersrdquo Separation andPurification Technology vol 52 no 1 pp 136ndash141 2006

[10] S Khoufi F Aloui and S Sayadi ldquoTreatment of olive oil millwastewater by combined process electro-Fenton reaction andanaerobic digestionrdquo Water Research vol 40 no 10 pp 2007ndash2016 2006

[11] P Canizares L Martınez R Paz C Saez J Lobato and MA Rodrigo ldquoTreatment of Fenton-refractory olive oil millwastes by electrochemical oxidation with boron-doped dia-mond anodesrdquo Journal of Chemical Technology and Biotechnol-ogy vol 81 no 8 pp 1331ndash1337 2006

[12] L Rizzo G Lofrano M Grassi and V Belgiorno ldquoPre-treatment of olive mill wastewater by chitosan coagulationand advanced oxidation processesrdquo Separation and PurificationTechnology vol 63 no 3 pp 648ndash653 2008

[13] U T Un U Altay A S Koparal and U B Ogutveren ldquoCom-plete treatment of olive mill wastewaters by electrooxidationrdquoChemical Engineering Journal vol 139 no 3 pp 445ndash452 2008

[14] W K Lafi B Shannak M Al-Shannag Z Al-Anber and MAl-Hasan ldquoTreatment of olive mill wastewater by combinedadvanced oxidation and biodegradationrdquo Separation and Purifi-cation Technology vol 70 no 2 pp 141ndash146 2009

[15] P Canizares R Paz C Saez and M A Rodrigo ldquoCosts ofthe electrochemical oxidation of wastewaters a comparisonwith ozonation and Fenton oxidation processesrdquo Journal ofEnvironmental Management vol 90 no 1 pp 410ndash420 2009

[16] P Grafias N P Xekoukoulotakis D Mantzavinos and EDiamadopoulos ldquoPilot treatment of olive pomace leachate by


vertical-flow constructed wetland and electrochemical oxida-tion an efficient hybrid processrdquo Water Research vol 44 no9 pp 2773ndash2780 2010

[17] N Papastefanakis D Mantzavinos and A Katsaounis ldquoDSAelectrochemical treatment of olive mill wastewater on TiRuO

2

anoderdquo Journal of Applied Electrochemistry vol 40 no 4 pp729ndash737 2010

[18] P Paraskeva and E Diamadopoulos ldquoTechnologies for olivemill wastewater (OMW) treatment a reviewrdquo Journal of Chem-ical Technology and Biotechnology vol 81 no 9 pp 1475ndash14852006

[19] B De Caprariis M Di Rita M Stoller N Verdone and AChianese ldquoReaction-precipitation by a spinning disc reactorinfluence of hydrodynamics on nanoparticles productionrdquoChemical Engineering Science vol 76 pp 73ndash80 2012

[20] O Sacco M Stoller V Vaiano P Ciambelli A Chianese andD Sannino ldquoPhotocatalytic degradation of organic dyes undervisible light on n-doped photocatalystsrdquo International JournalPhotoenergy vol 2012 Article ID 626759 8 pages 2012

[21] J M Ochando-Pulido M Stoller M Bravi A Martinez-Ferez and A Chianese ldquoBatch membrane treatment of olivevegetationwastewater from two-phase olive oil production pro-cess by threshold flux based methodsrdquo Separation PurificationTechnology vol 101 pp 34ndash41 2012

[22] A Fujishima and K Honda ldquoElectrochemical photolysis ofwater at a semiconductor electroderdquo Nature vol 238 no 5358pp 37ndash38 1972

[23] V Tyrpekl J P Vejpravova A G Roca N Murafa L SzatmaryandD Niznansky ldquoMagnetically separable photocatalytic com-posite 120574-Fe

2O3TiO

2synthesized by heterogeneous precipita-

tionrdquo Applied Surface Science vol 257 no 11 pp 4844ndash48482011

[24] M Ye Q Zhang Y Hu et al ldquoMagnetically recoverable core-shell nanocomposites with enhanced photocatalytic activityrdquoChemistry vol 16 pp 6243ndash6250 2010

[25] A Schatz M Hager and O Reiser ldquoCu(II)-azabis(oxazoline)-complexes immobilized on superparamagnetic magnetitesilica-nanoparticles a highly selective and recyclable catalystfor the kinetic resolution of 12-diolsrdquo Advanced FunctionalMaterials vol 19 no 13 pp 2109ndash2115 2009

[26] C Hui C Shen J Tian et al ldquoCore-shell Fe3O4SiO

2nanopar-

ticles synthesized with well-dispersed hydrophilic Fe3O4seedsrdquo

Nanoscale vol 3 no 2 pp 701ndash705 2011[27] TAGad-Allah S Kato S Satokawa andTKojima ldquoTreatment

of synthetic dyes wastewater utilizing a magnetically separablephotocatalyst (TiO

2SiO2Fe3O4) parametric and kinetic stud-

iesrdquo Desalination vol 244 no 1ndash3 pp 1ndash11 2009[28] S Abramson L Srithammavanh J-M Siaugue O Horner X

Xu and V Cabuil ldquoNanometric core-shell-shell 120574-Fe2O3SiO2

TiO2particlesrdquo Journal of Nanoparticle Research vol 11 no 2

pp 459ndash465 2009[29] B De Caprariis M Di Rita M Stoller N Verdone and A

Chianese ldquoReaction-precipitation by a spinning disc reactorinfluence of hydrodynamics on nanoparticles productionrdquoChemical Engineering Science vol 76 pp 73ndash80 2012

[30] X Jin A Jawor S Kim and EM VHoek ldquoEffects of feed watertemperature on separation performance and organic fouling ofbrackish water RO membranesrdquo Desalination vol 238 no 1ndash3pp 346ndash359 2009

[31] S Hong and M Elimelech ldquoChemical and physical aspectsof natural organic matter (NOM) fouling of nanofiltration

membranesrdquo Journal of Membrane Science vol 132 no 2 pp159ndash181 1997

[32] G Li L Li J Boerio-Goates and B F Woodfield ldquoHigh purityanatase TiO

2nanocrystals near room-temperature synthesis

grain growth kinetics and surface hydration chemistryrdquo Journalof the American Chemical Society vol 127 no 24 pp 8659ndash8666 2005

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy


Carbohydrate Chemistry

International Journal of


Journal of

Chemistry


Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of


Chromatography Research International


Applied ChemistryJournal of



Theoretical ChemistryJournal of


Journal of

Spectroscopy

Analytical ChemistryInternational Journal of


Journal of


Quantum Chemistry


Organic Chemistry International

ElectrochemistryInternational Journal of



CatalystsJournal of


Electron energy

E

UV-irradiation120582 lt 400nm

Conduction band

Valence band

Recombination of charges

32 eV

eminus

h+

Semiconductor (TiO2)

Adsorption (O2)

Oxidation (H+ + OH∙)Adsorption (H2O)

Adsorption(Pollutant P)

Deg

rada

tion

Reduction (O∙minus2 )

Pollutant P∙

Oxidation (P∙+)

Figure 1 Activation of the TiO2nanocatalyst by UV light

particular interest owed to its high oxidizing power of organiccontaminants along with its chemical stability and low cost[2] The key advantages of TiO

2UV light photocatalysis

process rely on the very high volume to surface ratio oftitania nanoparticles that lead to the absence of mass transferlimitationswhen nanoparticles are used as photocatalysts thepossibility of being triggered at ambient operating conditionsand to exploit sunlight instead of electric illumination incase of doped TiO

2 and the fact that TiO

2is a highly

active and nontoxic molecule capable of achieving completemineralization of a wide range of organic pollutants oroxidizing them into harmless compounds [3 4]

Olive oil factories commonly known as olive millsgenerate as by-product effluents (OME) an average dailyamount of 1m3 of wastewater derived from thewashing of theolives (oliveswashingwastewater OWW) togetherwithmorethan 10m3 of wastewater coming from the centrifugationprocess used for the extraction of the olive oil (olive oil millwastewater OMW) OMW exhibits a series of characteristicsthatmake their reclamation by conventional physicochemicaltreatments extremely difficult The presence of phytotoxicrefractory pollutants such as phenolic compounds organicacids tannins long chain fatty acids and organohalogenatedcontaminants makes these effluents recalcitrant to biologicaldegradation and thus inhibits the efficiency of biologicalprocesses Moreover the physicochemical composition ofOMW is extremely variable as it depends on several factorssuch as the extraction process edaphoclimatic and cultiva-tion parameters as well as the type quality and maturityof the olives [5ndash7] OMW typically exhibit strong odornuisance acid pH intensive violet-dark color considerablesaline toxicity reflected by high electroconductivity (EC)values and very heavy organic pollutants load [5] Additionaldifficulties such as small size and geographical dispersion ofolive oil mills as well as seasonality of olive oil production arefaced in the management of these agroindustry effluents

In this research work the treatment of the effluentsgenerated by olive mills working with the two-phase oliveoil extraction process (OMW-2) by TiO

2UV light photo-

catalysis is addressed The aforementioned set of featureshighlight TiO

2UV light photocatalysis as a potential AOP

from a technical and economical point of view if comparedwith other AOPs for the treatment of industrial effluentspresenting high organic matter (COD) pollutants load [8ndash20] However the main handicap in applying photocatalyticprocesses for the reclamation of industrial and agrofoodeffluents relies in the cost of the catalyst In this sensethe difficulty in recovering the catalyst poses the maintechnical-economical drawback To solve this problem anovel photocatalyst with ferromagnetic properties for ease ofrecovery and high effectiveness in the treatment of OMW-2 was developed Also the evolution of the organic matter(COD) and degradation rates were determined

2 Experimental

21 Feedstocks Olive Oil Washing Wastewater (OMW)and Mixture of Olives and Olive Oil Washing Wastewater(MOMW) Samples of OWW from the washing machinesand OMW at the outlet of the vertical centrifuges weretaken from an olive oil mill located in Jaen (Spain) operatingwith the modern two-phase olive oil extraction procedure[5] Two different raw feedstocks were used for the presentinvestigation on one hand OMW and on the other a 1 1(vv) mixture of olives and olive oil washing wastewater(MOMW) The physicochemical characteristics of both rawfeedstocks are reported in Table 1

As it can be noted the organic load in the effluent fromthe vertical centrifugation (OMW) is much higher than thatfrom the washing of the olives (OWW) andMOMW and thesame occurs for the concentration of phenolic compounds













2are being


2


2


2[24] Very recently
















3 HCl










Liquid feed


Water cooled

wall

Product

Heater

Spinning DISC









2catalyst






2SO3


3

supplied by Panreac







35

30

25

20

15

10

05

00

0 20 40 60

pH = 2

pH = 25

pH = 3

pH = 35

pH = 6

pH = 65pH = 7

TSS

in su

pern

atan

t (g L

minus1)

040

035

030

025

020

015

010

000

pH = 2

pH = 25

pH = 35

pH = 6

pH = 7

TSS

in su

pern

atan

t (g L

minus1)

005

0 20 40 60

T (∘C) T (∘C)









2


2layers




ΔCOD = 119861 sdot ln (119905) + ΔCOD (05) (5)


2







Cps (

eV)

120574-Fe2O3core



2 3 4 5 6 7 8 9 101

00

05

10

15

20

25

30

TiCO Si Ti

FeFe

(keV)


100

75

50

25

0

500 50000

Diameter (nm)

Num

ber


(a) (b)













0

5

10

15

20

25

0 50 100 150 200 250 3000

5

10

15

20

25

0 50 100 150 200 250 300

0

10

20

30

40

50

60

70

0 50 100 150 200 250 3000

10

20

30

40

50

60

70

0 50 100 150 200 250 300

(a998400) (b998400)

(a) (b)

minusΔ

COD

()

t (min)

minusΔ

COD

()

t (min)

minusΔ

COD

()

minusΔ

COD

()

t (min) t (min)





CODfinalg Lminus1

minusΔCOD4h

ΔCOD (05)g Lminus1

Bg Lminus1 hminus1


Degussa P-25

1 121 165 13 263 118 186 25 299 115 207 28 3320 118 186 27 30

Ferromag TiO2

1 114 214 25 323 125 133 16 229 131 103 06 16


Degussa P-251 17 543 101 923 16 565 100 939 15 570 101 95

Ferromag TiO2

05 15 584 98 931 16 557 100 913 17 527 99 87







4 Conclusions




2reaction




Acknowledgments


References























2








2O3TiO






2nanopar-

























Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of













2are being


2


2


2[24] Very recently
















3 HCl










Liquid feed


Water cooled

wall

Product

Heater

Spinning DISC









2catalyst






2SO3


3

supplied by Panreac







35

30

25

20

15

10

05

00

0 20 40 60

pH = 2

pH = 25

pH = 3

pH = 35

pH = 6

pH = 65pH = 7

TSS

in su

pern

atan

t (g L

minus1)

040

035

030

025

020

015

010

000

pH = 2

pH = 25

pH = 35

pH = 6

pH = 7

TSS

in su

pern

atan

t (g L

minus1)

005

0 20 40 60

T (∘C) T (∘C)









2


2layers




ΔCOD = 119861 sdot ln (119905) + ΔCOD (05) (5)


2







Cps (

eV)

120574-Fe2O3core



2 3 4 5 6 7 8 9 101

00

05

10

15

20

25

30

TiCO Si Ti

FeFe

(keV)


100

75

50

25

0

500 50000

Diameter (nm)

Num

ber


(a) (b)













0

5

10

15

20

25

0 50 100 150 200 250 3000

5

10

15

20

25

0 50 100 150 200 250 300

0

10

20

30

40

50

60

70

0 50 100 150 200 250 3000

10

20

30

40

50

60

70

0 50 100 150 200 250 300

(a998400) (b998400)

(a) (b)

minusΔ

COD

()

t (min)

minusΔ

COD

()

t (min)

minusΔ

COD

()

minusΔ

COD

()

t (min) t (min)





CODfinalg Lminus1

minusΔCOD4h

ΔCOD (05)g Lminus1

Bg Lminus1 hminus1


Degussa P-25

1 121 165 13 263 118 186 25 299 115 207 28 3320 118 186 27 30

Ferromag TiO2

1 114 214 25 323 125 133 16 229 131 103 06 16


Degussa P-251 17 543 101 923 16 565 100 939 15 570 101 95

Ferromag TiO2

05 15 584 98 931 16 557 100 913 17 527 99 87







4 Conclusions




2reaction




Acknowledgments


References























2








2O3TiO






2nanopar-

























Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


Liquid feed


Water cooled

wall

Product

Heater

Spinning DISC









2catalyst






2SO3


3

supplied by Panreac







35

30

25

20

15

10

05

00

0 20 40 60

pH = 2

pH = 25

pH = 3

pH = 35

pH = 6

pH = 65pH = 7

TSS

in su

pern

atan

t (g L

minus1)

040

035

030

025

020

015

010

000

pH = 2

pH = 25

pH = 35

pH = 6

pH = 7

TSS

in su

pern

atan

t (g L

minus1)

005

0 20 40 60

T (∘C) T (∘C)









2


2layers




ΔCOD = 119861 sdot ln (119905) + ΔCOD (05) (5)


2







Cps (

eV)

120574-Fe2O3core



2 3 4 5 6 7 8 9 101

00

05

10

15

20

25

30

TiCO Si Ti

FeFe

(keV)


100

75

50

25

0

500 50000

Diameter (nm)

Num

ber


(a) (b)













0

5

10

15

20

25

0 50 100 150 200 250 3000

5

10

15

20

25

0 50 100 150 200 250 300

0

10

20

30

40

50

60

70

0 50 100 150 200 250 3000

10

20

30

40

50

60

70

0 50 100 150 200 250 300

(a998400) (b998400)

(a) (b)

minusΔ

COD

()

t (min)

minusΔ

COD

()

t (min)

minusΔ

COD

()

minusΔ

COD

()

t (min) t (min)





CODfinalg Lminus1

minusΔCOD4h

ΔCOD (05)g Lminus1

Bg Lminus1 hminus1


Degussa P-25

1 121 165 13 263 118 186 25 299 115 207 28 3320 118 186 27 30

Ferromag TiO2

1 114 214 25 323 125 133 16 229 131 103 06 16


Degussa P-251 17 543 101 923 16 565 100 939 15 570 101 95

Ferromag TiO2

05 15 584 98 931 16 557 100 913 17 527 99 87







4 Conclusions




2reaction




Acknowledgments


References























2








2O3TiO






2nanopar-

























Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


35

30

25

20

15

10

05

00

0 20 40 60

pH = 2

pH = 25

pH = 3

pH = 35

pH = 6

pH = 65pH = 7

TSS

in su

pern

atan

t (g L

minus1)

040

035

030

025

020

015

010

000

pH = 2

pH = 25

pH = 35

pH = 6

pH = 7

TSS

in su

pern

atan

t (g L

minus1)

005

0 20 40 60

T (∘C) T (∘C)









2


2layers




ΔCOD = 119861 sdot ln (119905) + ΔCOD (05) (5)


2







Cps (

eV)

120574-Fe2O3core



2 3 4 5 6 7 8 9 101

00

05

10

15

20

25

30

TiCO Si Ti

FeFe

(keV)


100

75

50

25

0

500 50000

Diameter (nm)

Num

ber


(a) (b)













0

5

10

15

20

25

0 50 100 150 200 250 3000

5

10

15

20

25

0 50 100 150 200 250 300

0

10

20

30

40

50

60

70

0 50 100 150 200 250 3000

10

20

30

40

50

60

70

0 50 100 150 200 250 300

(a998400) (b998400)

(a) (b)

minusΔ

COD

()

t (min)

minusΔ

COD

()

t (min)

minusΔ

COD

()

minusΔ

COD

()

t (min) t (min)





CODfinalg Lminus1

minusΔCOD4h

ΔCOD (05)g Lminus1

Bg Lminus1 hminus1


Degussa P-25

1 121 165 13 263 118 186 25 299 115 207 28 3320 118 186 27 30

Ferromag TiO2

1 114 214 25 323 125 133 16 229 131 103 06 16


Degussa P-251 17 543 101 923 16 565 100 939 15 570 101 95

Ferromag TiO2

05 15 584 98 931 16 557 100 913 17 527 99 87







4 Conclusions




2reaction




Acknowledgments


References























2








2O3TiO






2nanopar-

























Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


Cps (

eV)

120574-Fe2O3core



2 3 4 5 6 7 8 9 101

00

05

10

15

20

25

30

TiCO Si Ti

FeFe

(keV)


100

75

50

25

0

500 50000

Diameter (nm)

Num

ber


(a) (b)













0

5

10

15

20

25

0 50 100 150 200 250 3000

5

10

15

20

25

0 50 100 150 200 250 300

0

10

20

30

40

50

60

70

0 50 100 150 200 250 3000

10

20

30

40

50

60

70

0 50 100 150 200 250 300

(a998400) (b998400)

(a) (b)

minusΔ

COD

()

t (min)

minusΔ

COD

()

t (min)

minusΔ

COD

()

minusΔ

COD

()

t (min) t (min)





CODfinalg Lminus1

minusΔCOD4h

ΔCOD (05)g Lminus1

Bg Lminus1 hminus1


Degussa P-25

1 121 165 13 263 118 186 25 299 115 207 28 3320 118 186 27 30

Ferromag TiO2

1 114 214 25 323 125 133 16 229 131 103 06 16


Degussa P-251 17 543 101 923 16 565 100 939 15 570 101 95

Ferromag TiO2

05 15 584 98 931 16 557 100 913 17 527 99 87







4 Conclusions




2reaction




Acknowledgments


References























2








2O3TiO






2nanopar-

























Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


0

5

10

15

20

25

0 50 100 150 200 250 3000

5

10

15

20

25

0 50 100 150 200 250 300

0

10

20

30

40

50

60

70

0 50 100 150 200 250 3000

10

20

30

40

50

60

70

0 50 100 150 200 250 300

(a998400) (b998400)

(a) (b)

minusΔ

COD

()

t (min)

minusΔ

COD

()

t (min)

minusΔ

COD

()

minusΔ

COD

()

t (min) t (min)





CODfinalg Lminus1

minusΔCOD4h

ΔCOD (05)g Lminus1

Bg Lminus1 hminus1


Degussa P-25

1 121 165 13 263 118 186 25 299 115 207 28 3320 118 186 27 30

Ferromag TiO2

1 114 214 25 323 125 133 16 229 131 103 06 16


Degussa P-251 17 543 101 923 16 565 100 939 15 570 101 95

Ferromag TiO2

05 15 584 98 931 16 557 100 913 17 527 99 87







4 Conclusions




2reaction




Acknowledgments


References























2








2O3TiO






2nanopar-

























Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of







4 Conclusions




2reaction




Acknowledgments


References























2








2O3TiO






2nanopar-

























Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of




2








2O3TiO






2nanopar-

























Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of










Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of

research article a novel photocatalyst with ferromagnetic...

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