research article advanced treatment of pesticide...

Research ArticleAdvanced Treatment of Pesticide-ContainingWastewater Using Fenton Reagent Enhanced by MicrowaveElectrodeless Ultraviolet

Gong Cheng1 Jing Lin1 Jian Lu1 Xi Zhao1 Zhengqing Cai2 and Jie Fu3

1Shenzhen Academy of Environmental Sciences Shenzhen 518001 China2Environmental Engineering Program Department of Civil Engineering Auburn University Auburn AL 36849 USA3School of Civil and Environmental Engineering Georgia Institute of Technology Atlanta GA 30332 USA

Correspondence should be addressed to Zhengqing Cai zzc0008tigermailauburnedu and Jie Fu jiefucegatechedu

Received 17 February 2015 Revised 21 April 2015 Accepted 21 April 2015

Academic Editor Qaisar Mahmood

Copyright copy 2015 Gong Cheng 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 photo-Fenton reaction is a promising method to treat organic contaminants in water In this paper a Fenton reagent enhancedby microwave electrodeless ultraviolet (MWEUVFenton) method was proposed for advanced treatment of nonbiodegradableorganic substance in pesticide-containing biotreated wastewater MWEUV lamp was found to be more effective for chemicaloxygen demand (COD) removal than commercial mercury lamps in the Fenton process The pseudo-first order kinetic modelcan well describe COD removal from pesticide-containing wastewater by MWEUVFenton and the apparent rate constant(k) was 00125minminus1 The optimal conditions for MWEUVFenton process were determined as initial pH of 5 Fe2+ dosage of08mmolL and H

2

O2

dosage of 100mmolL Under the optimal conditions the reaction exhibited high mineralization degrees oforganics where COD and dissolved organic carbon (DOC) concentration decreased from 1832mgL to 369mgL and 435mgLto 278mgL respectively Three main pesticides in the wastewater as Dimethoate Triazophos and Malathion were completelyremoved by the MWEUVFenton process within 120min The high degree of pesticides decomposition and mineralization wasproved by the detected inorganic anions

1 Introduction

The widespread use of pesticides in the past decades rep-resents serious water pollutants [1] Various types of pes-ticides residues were frequently detected in surface waterand aroused great public concern The pesticides will causepotential adverse health risks even at low concentration(pgL to ngL) [2]These pesticides retained in agrochemicalwastewater are resistant to conventional biological treatmentowing to their high toxicity and biological persistence Itwas reported that no significant decrease in pesticide contentoccurred after the biological treatment and remaining recal-citrant organic carbon mainly due to pesticide molecules [3]

Advanced oxidation processes (AOPs) were expectedto decompose those typically stable products into carbondioxide water and inorganics or at least transform them

into harmless compounds [4] AOPs have been successfullyapplied for the removal of recalcitrant substances fromorganic wastewater in recent years [5ndash8] Among AOPsphoto-Fenton is considered as a promising process to gen-erate oxidizing species for pollutants degradation [9 10]Photo-Fenton reaction requires the presence of Fe2+ andhydrogen peroxide under the UV radiation to produce highlyoxidative hydroxyl radicals which react with the organic pol-lutants and lead to the complete mineralization [11] Photo-Fenton is effective in treatingwastewater with various organiccontaminants such as dye [12] 24-dichlorophenol [13]and nonylphenol polyethoxylate [14] It has been concludedthat the introduction of UV light significantly promotesthe degradation efficiency by photoreducing Fe3+ to Fe2+and producing additional hydroxyl radicals Thus UV lightsource is a crucial design of photo-Fenton reactor

Hindawi Publishing CorporationBioMed Research InternationalVolume 2015 Article ID 205903 8 pageshttpdxdoiorg1011552015205903

2 BioMed Research International

Microwave electrodeless ultraviolet (MWEUV) was anew-type UV light source developed in recent years [15 16]It includes a mercury vapor lamp powered by microwaveenergy and emitted stable UV radiation The MWEUVlamp would lead to a further development of simple andhigh efficiency photochemical reactor owing to its uniqueadvantages [17ndash19] highUV radiant power long lifetime andbeing immersed into reaction solution with adaptable lampshapes Particularly both UV and microwave radiations areavailable simultaneously by using microwave energy Manystudies have reported successful applications of MWEUVlamp as light source in photolysis [20] UVH

2

O2

[21]and heterogeneous or homogeneous photocatalysis pro-cesses [22ndash24] for organic wastewater treatment It has beenproved that the simultaneous application ofmicrowave powerand UV light exhibits higher efficiency in photochemicalprocesses

In recent years several advanced oxidation processesfor the treatment of pesticide-containing wastewater havebeen proposed However the degradation efficiency forrecalcitrant pesticide substances did not meet the demandof commercial application In this research the MWEUVlamp was employed for enhancing Fenton process to removenonbiodegradable organic pesticide in pesticide-containingeffluent after biotreatment Optimal parameters for CODremoval by the MWEUVFenton process were determinedOxidation degree andmineralization performance of residualpesticide in wastewater were also evaluated in terms ofaverage oxidation state (AOS) carbon oxidation state (COS)DOC and inorganic anions concentration

2 Experimental Methodology

21 Materials and Reagents Fresh wastewater was gener-ated from pesticide container washing process in a chem-ical products estate (Guangdong China) The sequentialprocesses coagulation precipitation and biodegradationhave been employed for elimination of suspended solidsand biodegradable organic substances from the pesticide-containing wastewater Physicalchemical characteristics offresh wastewater and the biotreated wastewater were showedin Table 1 The concentration of COD and pesticides ineffluent wastewater without any advanced treatments stillexceeded the discharge limits imposed by Discharge Limitsof Water Pollutants (Local Standard DB4426-2001)

H2

O2

(30 ww) and FeSO4

sdot7H2

O were prepared ata predetermined concentration as Fenton reagent H

2

SO4

(10mmolL) and NaOH (10mmolL) were used for pHadjustment All chemicals were of analytical grade purchasedfrom Sinopharm Chemical Reagent Co Ltd (ShenzhenChina)

22 Experimental Setup andMethods AU-shapedMWEUVlamp was used in this study The lamp is made by quartztubes filled with 1mg mercury and 066 kPa argon Theexternal diameter is 20mm and effective length is 250mmThe MWEUV lamp had prominent UV emission bands at254 313 365 and 405 nm Microwave generator (Haier Co

Table 1 Physicalchemical characteristics of fresh wastewater andthe biotreated wastewater

Concentration(mgL) Fresh wastewater Effluent after

biological treatmentpH 60sim68

sim70TSS 61885 plusmn 7090

lt15COD 154034 plusmn 20212 1832 plusmn 995BOD5 33658 plusmn 2086

lt15Dimethoate(C5H12NO3PS2)

1566 plusmn 338 1471 plusmn 079

Triazophos(C12H16N3O3PS)

611 plusmn 063 587 plusmn 089

Malathion(C10H19O6PS2)

3165 plusmn 477 2453 plusmn 416

Microwavegenerator

Microwave

Magneticstirrer

MWEUV lamp

Glass reactor

Solution

Sealing flange

Pump

Cooling water inlet

Cooling wateroutlet

Thermometer

Sampling port

Figure 1 Schematic diagram of experimental setup

Ltd China) was operated with 80W output at frequency of245GHzThe output power ofMWEUV lampwasmeasuredby monitoring the temperature of the solution with andwithout the MWEUV lamp [25] According the calculationapproximate 40Wwas supplied to excite MWEUV lamp andthe rest power was consumed or converted to heat

Schematic diagram of the experimental setup is shown inFigure 1 1000mL pesticide-containingwastewater was addedin the glass cylindrical reactor (available capacity of 1000mL)Then required dosage of Fenton reagent was added intothe solution and mixed by a magnetic stirrer (HJ-3 JingdaInstrument Company China) Microwave generator wasapplied to excited MWEUV lamp emitting UV irradiationduring the reaction Solution temperature during the reactionwas kept constant at 25 plusmn 05∘C by circulating solution to acooler with a pump (DP-60 Seisun pumps Co Ltd China)Samples were withdrawn at predetermined time intervalsand the final pH values were adjusted to lower than 3 beforeanalysis All the runs were triplicated

In this study the experiments were carried out as followsand the results were compared (1) Fenton oxidation run(2) UVFenton run assisted by a commercial UV mer-cury lamp (40W of output CREATOR China) and (3)MWEUVFenton run assisted by MWEUV lamp

BioMed Research International 3

23 Analytical Methods The pH value of solution was mea-sured using a pH meter (PHB-5 INESA Instrument China)Total suspended solids (TSS) were measured by gravimetrymethod Chemical oxygen demand (COD) was determinedaccording to the Standard Methods [26] Dissolved organiccarbon (DOC) was measured by TOC analyzer (Multi NCJena) NO

3

minus SO4

2minus and PO4

3minus were quantified by ionchromatography (Dionex ICS-900 column Ion Pac AS23suppressor MMS 300) Isocratic elution was done with KOHsolution at a flow rate of 10mLmin for anions analyzedThequantitative analysis of pesticides was performed by GCMS(Agilent 6890N-5975B) Samples were subsequently injectedin GC coupled with a mass spectrometer The mass detectorwas operated inMRM(Multiple ReactionMonitoring)modeselecting specific transitions for each pesticide The finaloptimized method allowed the concurrent detection of threepesticides during chromatographic runs of 20min

3 Results and Discussion

31 Evaluation of Different Treatment Processes Photo-Fenton process produces hydroxyl radicals with powerfuloxidizing ability to degrade organic pollution The majorreactions to form hydroxyl radicals are as follows [5]

Fe2+ +H2

O2

997888rarr Fe3+ + ∙OH +OHminus (1)

Fe3+ +H2

O 997888rarr Fe (OH)2+ +H+ (2)

Fe (OH)2+ℎ]997888rarr Fe2+ + ∙OH (3)

H2

O2

ℎ]997888rarr ∙OH + ∙OH (4)

In this study treatment of pesticide-containing wastew-ater in different processes was evaluated Specially Fentonoxidation assisted by MWEUV and a commercial mercuryUV lamp was compared As shown in Figure 2 Fentonoxidation only achieved 487ofCOD removal after 120minwhile COD removal efficiency was significantly improved byintroducing UV light The COD concentration of pesticide-containing wastewater with UVFenton treatment decreased640 Such improvement was attributed to two facts on theone hand the reduction of Fe3+ (Equations (2) (3)) underUV irradiation regenerated Fe2+ that can further participatein the Fenton reaction and produce ∙OH radicals Suchrecycling enhanced the ∙OH radical production and providestheUVFenton system sufficient activity for organicmoleculedecomposition On the other hand photolysis of H

2

O2

(Equation (4)) generates more OH radicals It is also notablethat MWEUV lamp as the light source is more effective inthe Fenton system than a commercial mercury lamp 721of COD in wastewater was removed by MWEUVFentontreatment within 120min In this experiment wastewatertemperature during the reaction was kept constant It meansthat microwave irradiation accelerates chemical reactionsby nonthermal effects such as polarization dielectric prop-erties nuclear spin rotation and spin alignment [27] Itwas reported that simultaneous irradiation of microwaveand UV-Vis light led to effective reactant decomposition

0 30 60 90 1200

20

40

60

80

COD

rem

oval

()

Time (min)

FentonUVFentonMWEUVFenton

Figure 2 COD removal in different treatment processes Experi-mental conditions initial pH value of 5 H

2

O2

dosage of 40mmolLand Fe2+ dosage of 06mmolL

by microwave ultraviolet electrodeless lamp introduced inphotolysis photocatalysis andUVH

2

O2

systems [25 27 28]

32 Effect of Initial pH Value The pH of wastewater isan important parameter for the MWEUVFenton processbecause it affects the decomposition of hydrogen peroxide[29] and the hydrolytic speciation of the ferric ion species[30] To test the effect of initial pH experiments were carriedout at initial pH ranging from 2 to 10 the results of CODremoval by MWEUVFenton are shown in Figure 3(a) It isclear that removal efficiency is highly dependent on initialpH and the optimum pH is between 2 and 4 The CODremoval efficiency decreased from 738 to 417 accordingto the increase of pH from 5 to 9 Many researchers have alsoreported the optimum pH as 3ndash5 for conventional Fenton orphoto-Fenton processes [31ndash33] Neamtu et al [34] summa-rized various photoactive species of iron formed at differentpH conditionsThedominant species at pH 1-2 is Fe[H

2

O]6

3+2-3 is for Fe[OH][H

2

O]5

2+ and 3-4 is for Fe[OH]2

[H2

O]4

+Fe(OH)2+ species is reported to have the highest pho-toreactivity in Fentonrsquos oxidation [35] At acidic pH Fe3+hydroxyl complexes are highly soluble and Fe(OH)2+ isthe predominant form of the Fe3+ hydroxyl complexes Athigher pH the concentration of Fe[OH]2+ complex ions insolution decreased with the precipitation of ferrous ion asoxyhydroxides [36] Under the alkaline solution conditionthe removal of pollutant is mainly attributed to adsorptionand coagulation rather than Fenton oxidation [37]

33 Effect of H2

O2

Dosage Effect of H2

O2

dosage onCOD removal from pesticide-containing wastewater byMWEUVFenton is shown in Figure 3(b) As expected


2 4 6 8 10

40

50

60

70

80CO

D re

mov

al (

)

Initial pH value

(a)

20 40 60 80 100 12010

20

30

40

50

60

70

80

COD

rem

oval

()

H2O2 dosage (mmolL)

(b)

00 02 04 06 08 10

40

50

60

70

80

COD

rem

oval

()

Fe2+ dosage (mmolL)

(c)

Figure 3 Effect of (a) initial pH valuewithH2

O2

dosage of 40mmolL (b)H2

O2

dosage and (c) Fe2+ dosagewithH2

O2

dosage of 100mmolLon COD removal General experimental parameters initial pH value of 5 Fe2+ dosage of 06mmolL and reaction time of 120min

the increase of H2

O2

dosage from 20 to 80mmolL accel-erated COD removal The increased degradation efficiencycan be attributed to the additional OH radicals producedfrom H

2

O2

decomposition However COD removal couldnot be obviously improved by excessive addition of H

2

O2

(gt100mmolL)The results showed a negligible increase from775 to 783 in removal efficiency when H

2

O2

dosage fur-ther increased from 100 to 120mmolL It can be interpretedthat the excessive H

2

O2

acts as a scavenger of ∙OH but theproduced HO

2

∙ (Equations (5)ndash(7)) has much lower oxida-tion capacities [38] Therefore the optimum H

2

O2

dosagewas found to be 100mmolL for advanced treatment of thepesticide-containing wastewater by the MWEUVFenton

H2

O2

+ ∙OH 997888rarr HO2

∙ +H2

O (5)HO2

∙ +OH 997888rarr H2

O +O2

(6)

∙OH + ∙OH 997888rarr H2

O2

(7)

Li et al [39] investigated catechol oxidation in nano-Fe3

O4

catalyzing UV-Fenton process The best operationalH2

O2

dosage was determined to obtain high efficiency ofboth H

2

O2

utilization and COD removal Lucas and Peres[40] observed the decreasing dye decolorization at excessiveH2

O2

concentration (gt2mmolL) for Reactive Black 5 inFentonUV-C and ferrioxalateH

2

O2

solar light processesZhong et al [41] also indicated that the degradation efficiencyof tetrabromobisphenol A significantly decreased in hetero-geneous UVFenton with the H

2

O2

concentration increasingto 20mmolL

34 Effect of Fe2+ Dosage To investigate effect of Fe2+ dosageon COD removal experiments were carried out at Fe2+dosage ranging from 0 to 10mmolL Figure 3(c) showeda significant increase in COD removal efficiency from445 to 779 with the increasing Fe2+ concentration 0 to


08mmolL Fe2+ is important for formation of photoactiveferric-hydroxo complexes that absorb UV light to produce∙OH [42] However further increases in Fe2+ concentrationup to 08mmolL only resulted in slight increases indegradation rate Excessive ferrous ions may act as hydroxylradical scavenger according to the following [43]

Fe2+ + ∙OH 997888rarr Fe3+ +OHminus (8)

In addition a deep color and high turbidity at highFe2+ concentration reduced the transmission of UV light insolution which inhibited the photolysis of H

2

O2

to produceOHradicals [31]Therefore overdosed Fe2+ was inefficient forCOD removal by MWEUVFenton process

35 Kinetics of COD Removal by MWEUVFenton Experi-ments were conducted under the optimum operating condi-tions to evaluate the kinetics ofMWEUVFentondegradationfor pesticide-containing wastewater A simple pseudo-firstorder kinetic model was used to fit experimental data anddetermine the kinetic parameters

minus ln119862119905

119862

0

= 119896119905 (9)

where 119862119905

is COD concentration (mgL) at time 119905 (min)119862

0

is initial COD concentration (mgL) and 119896 is apparentrate constant (minminus1) A plot of minusln(119862

119905

119862

0

) versus 119905 gen-erates a straight line Apparent rate constant for the CODdegradation was determined from the slope of the straightline From Figure 4 COD degradation in MWEUVFentonfollowed pseudo-first order kinetics with rate constants (119896) of00125minminus1 and 1198772 (correlation coefficient) of 09171

36 Evaluation of Oxidation Degree and Mineralization Atpresent two parameters as AOS and COS are defined toevaluate the oxidation degree and oxidative process efficiencyrespectively [3]

AOS = 4 minus 15 (COD119905

DOC119905

) (10)

COS = 4 minus 15 (COD119905

DOC0

) (11)

where COD119905

is the chemical oxygen demand (mgL) at time119905 (min) DOC

119905

is the dissolved organic carbon (mgL) at time119905 and DOC

0

is the initial dissolved organic carbon (mgL)AOS takes values between +4 for CO

2

themost oxidized stateof C and minus4 for CH

4

the most reduced state of CFigures 5 and 6 present the evolution of CODDOCAOS

and COS with reaction time Both the initial AOS and COSparameters were minus232 indicating that organic compoundsare at reduced state in wastewater With the prolongingof reaction time the concentrations of COD and DOC inwastewater gradually decreased showing a strong oxidationof the organics AOS and COS parameters increased tobe positive suggesting that strong mineralization occurredand highly oxidized intermediates are generated Analyzing

0 30 60 90 12000

05

10

15

20

t (min)

minusln

(CtC0)

Figure 4 Kinetics of COD decomposition by MWEUVFentonExperimental parameters initial pH value of 5 H

2

O2

dosage of100mmolL and Fe2+ dosage of 08mmolL

0 1 2 3 4 5 6 7 820406080

100120140160180200

COD

conc

entr

atio

n(m

gL)

Time (h)

20253035404550

DO

C co

ncen

trat

ion

(mg

L)

Figure 5 Evolution of COD and DOC in MWEUVFentonExperimental parameters initial pH value of 5 H

2

O2


the different process phases more oxidized organic inter-mediates were formed before 60min of reaction withoutsubstantial mineralization which is corroborated by rapidCOD decrease and low DOC removal After the gradualgrowth the values of AOS and COS reached the plateauFinally the concentrations of COD and DOC decreased to369mgL and 278mgL respectively with the AOS value of273 and the COS value of 201The results indicate that a highoxidation degree of pesticides related to the generation ofsome lowmolecular weight carbohydrates which are resistantto mineralization by hydroxyl radicals

The concentration profiles of Dimethoate Triazophosand Malathion during the MWEUVFenton process areshown in Figure 7 They displayed similar profiles a rapid


0 1 2 3 4 5 6 7 8minus3

minus2

minus1

0

1

2

3AO

S C

OS

Time (h)

AOSCOS

Figure 6 Evolution of AOS and COS in MWEUVFentonExperimental parameters initial pH value of 5 H

2

O2


2426

2220181614121086420

Con

cent

ratio

n (m

gL)

060

120180

240

Time (min) Triazophos

Dimethoate

Malathion

Figure 7 Degradation of Dimethoate Triazophos and Malathionin MWEUVFenton Experimental parameters initial pH value of5 H2

O2

dosage of 100mmolL and Fe2+ dosage of 08mmolL

increase in pesticides concentration at the initial stage ofMWEUVFenton process and Dimethoate and Malathionwere completely removed within 240min Figure 8 exhibitsthe concentration changes of inorganic anions (NO

3

minus SO4

2minusand PO

4

3minus) in the reaction The increases of SO4

2minus andPO4

3minus concentration in wastewater were mainly attributedto the breakage of chemical bonds such as S=P P-O andS-P The results also suggested a deep decomposition andmineralization of pesticide molecules occurring under theattack of hydroxyl radicals

0 30 60 90 120 150 180 210 2400

20

40

60

140

160

Con

cent

ratio

n (m

gL)

Time (min)

NO3minus

SO42minus

PO43minus

Figure 8 Evolution of inorganic anions in MWEUVFentonExperimental parameters initial pH value of 5 H

2

O2


4 Conclusions

The feasibility and superiority of the MWEUVFentonfor advanced treatment of pesticide-containing biotreatedwastewater were evaluated in this paper In terms of CODremoval the MWEUVFenton process showed high effi-ciency comparing with the conventional Fenton processassisted by commercial mercury lamps The optimal param-eters were found at the initial pH of 5 Fe2+ dosage of08mmolL and H

2

O2

dosage of 100mmolL Three mainpesticides Dimethoate Triazophos and Malathion in thewastewater were completely decomposedwith high oxidationand mineralization degrees

Conflict of Interests

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

Acknowledgment

This research was supported by Major Science and Tech-nology Program for Water Pollution Control and Treatment(2012ZX07206-004)

References

[1] C Zaror C Segura H Mansilla M A Mondaca and PGonzalez ldquoKinetic study of Imidacloprid removal by advancedoxidation based on photo-Fenton processrdquoEnvironmental Tech-nology vol 31 no 13 pp 1411ndash1416 2010

[2] K V Plakas and A J Karabelas ldquoRemoval of pesticides fromwater by NF and RO membranesmdasha reviewrdquo Desalination vol287 pp 255ndash265 2012


[3] V J P Vilar F C Moreira A C C Ferreira et alldquoBiodegradability enhancement of a pesticide-containing bio-treated wastewater using a solar photo-Fenton treatment stepfollowed by a biological oxidation processrdquoWater Research vol46 no 15 pp 4599ndash4613 2012

[4] M M Mico S Chourdaki J Bacardit and C Sans ldquoCom-parison between ozonation and photo-fenton processes forpesticide methomyl removal in advanced greenhousesrdquo OzoneScience amp Engineering vol 32 no 4 pp 259ndash264 2010

[5] A Babuponnusami and K Muthukumar ldquoA review on Fentonand improvements to the Fenton process for wastewater treat-mentrdquo Journal of Environmental Chemical Engineering vol 2no 1 pp 557ndash572 2014

[6] 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

[7] N Klamerth S Malato A Aguera A Fernandez-Alba and GMailhot ldquoTreatment of municipal wastewater treatment planteffluents with modified photo-fenton as a tertiary treatmentfor the degradation of micro pollutants and disinfectionrdquoEnvironmental Science amp Technology vol 46 no 5 pp 2885ndash2892 2012

[8] Q-F Zeng J Fu Y Zhou Y-T Shi and H-L Zhu ldquoPhotoox-idation degradation of Reactive brilliant red K-2BP in aqueoussolution by ultraviolet radiationsodium hypochloriterdquo CleanSoil Air Water vol 37 no 7 pp 574ndash580 2009

[9] Y Deng and J D Englehardt ldquoTreatment of landfill leachate bythe Fenton processrdquo Water Research vol 40 no 20 pp 3683ndash3694 2006

[10] C Orbeci I Untea G Nechifor A E Segneanu and M ECraciun ldquoEffect of a modified photo-Fenton procedure onthe oxidative degradation of antibiotics in aqueous solutionsrdquoSeparation and Purification Technology vol 122 pp 290ndash2962014

[11] M Umar H A Aziz and M S Yusoff ldquoTrends in the use ofFenton electro-Fenton and photo-Fenton for the treatment oflandfill leachaterdquo Waste Management vol 30 no 11 pp 2113ndash2121 2010

[12] J X Chen and L Z Zhu ldquoOxalate enhanced mechanismof hydroxyl-Fe-pillared bentonite during the degradation ofOrange II by UV-Fenton processrdquo Journal of Hazardous Mate-rials vol 185 no 2-3 pp 1477ndash1481 2011

[13] A Karci I Arslan-Alaton T Olmez-Hanci and M BekboletldquoTransformation of 24-dichlorophenol byH

2

O2

UV-C Fentonand photo-Fenton processes oxidation products and toxic-ity evolutionrdquo Journal of Photochemistry and Photobiology AChemistry vol 230 no 1 pp 65ndash73 2012

[14] A Karci I Arslan-Alaton M Bekbolet G Ozhan and BAlpertunga ldquoH

2

O2

UV-C and Photo-Fenton treatment of anonylphenol polyethoxylate in synthetic freshwater follow-up of degradation products acute toxicity and genotoxicityrdquoChemical Engineering Journal vol 241 pp 43ndash51 2014

[15] J Fu Z Xu Q-S Li et al ldquoTreatment of simulated wastewatercontaining Reactive Red 195 by zero-valent ironactivatedcarbon combined with microwave discharge electrodelesslampsodium hypochloriterdquo Journal of Environmental Sciencesvol 22 no 4 pp 512ndash518 2010

[16] J Fu T Wen Q Wang et al ldquoDegradation of Active BrilliantRed X-3B by a microwave discharge electrodeless lamp in the

presence of activated carbonrdquo Environmental Technology vol31 no 7 pp 771ndash779 2010

[17] A I Al-Shammarsquoa I Pandithas and J Lucas ldquoLow-pressuremicrowave plasma ultraviolet lamp for water purification andozone applicationsrdquo Journal of Physics D Applied Physics vol34 no 18 pp 2775ndash2781 2001

[18] J H Xu C L Li P Liu D He J F Wang and Q Zhang ldquoPho-tolysis of low concentration H

2

S under UVVUV irradiationemitted from high frequency discharge electrodeless lampsrdquoChemosphere vol 109 pp 202ndash207 2014

[19] S HorikoshiM Kajitani S Sato andN Serpone ldquoA novel envi-ronmental risk-free microwave discharge electrodeless lamp(MDEL) in advanced oxidation processes Degradation of the24-D herbiciderdquo Journal of Photochemistry and Photobiology AChemistry vol 189 no 2-3 pp 355ndash363 2007

[20] X Zhang Y Wang G Li and J Qu ldquoOxidative decompositionof azo dye CI Acid Orange 7 (AO7) under microwave elec-trodeless lamp irradiation in the presence of H

2

O2

rdquo Journal ofHazardous Materials vol 134 no 1ndash3 pp 183ndash189 2006

[21] C Ferrari I Longo E Tombari and E Bramanti ldquoA novelmicrowave photochemical reactor for the oxidative decompo-sition of Acid Orange 7 azo dye by MWUVH

2

O2

processrdquoJournal of Photochemistry and Photobiology A Chemistry vol204 no 2-3 pp 115ndash121 2009

[22] J Hong C Sun S-G Yang and Y-Z Liu ldquoPhotocatalyticdegradation of methylene blue in TiO

2

aqueous suspensionsusing microwave powered electrodeless discharge lampsrdquo Jour-nal of Hazardous Materials vol 133 no 1ndash3 pp 162ndash166 2006

[23] S Horikoshi M Kajitani N Horikoshi R Dillert and DW Bahnemann ldquoUse of microwave discharge electrodelesslamps (MDEL) II Photodegradation of acetaldehyde overTiO2

pelletsrdquo Journal of Photochemistry and Photobiology AChemistry vol 193 no 2-3 pp 284ndash287 2008

[24] S Horikoshi H Hidaka and N Serpone ldquoEnvironmentalremediation by an integrated microwaveUV-illuminationtechnique IV Non-thermal effects in the microwave-assisteddegradation of 24-dichlorophenoxyacetic acid in UV-irradiated TiO

2

H2

O dispersionsrdquo Journal of Photochemistryand Photobiology A Chemistry vol 159 no 3 pp 289ndash3002003

[25] X W Zhang G T Li Y Z Wang and J H Qu ldquoMicrowaveelectrodeless lamp photolytic degradation of acid orange 7rdquoJournal of Photochemistry and Photobiology A Chemistry vol184 no 1-2 pp 26ndash33 2006

[26] APHA Standard Methods for the Examination of Water andWastewater American Public Health Association WashingtonDC USA 21st edition 2005

[27] XW Zhang G T Li and Y ZWang ldquoMicrowave assisted pho-tocatalytic degradation of high concentration azo dye ReactiveBrilliant Red X-3B with microwave electrodeless lamp as lightsourcerdquo Dyes and Pigments vol 74 no 3 pp 536ndash544 2007

[28] D-H Han S-Y Cha and H-Y Yang ldquoImprovement of oxida-tive decomposition of aqueous phenol bymicrowave irradiationin UVH

2

O2

process and kinetic studyrdquoWater Research vol 38no 11 pp 2782ndash2790 2004

[29] Y-Y Zhang C He V-K Sharma X-Z Li S-H Tian andY Xiong ldquoA new reactor coupling heterogeneous Fenton-likecatalytic oxidation with membrane separation for degradationof organic pollutantsrdquo Journal of Chemical Technology andBiotechnology vol 86 no 12 pp 1488ndash1494 2011

[30] J-H Park I-H Cho and S-W Chang ldquoComparison ofFenton and Photo-Fenton processes for livestock wastewater


treatmentrdquo Journal of Environmental Science and Health Part BPesticides Food Contaminants and Agricultural Wastes vol 41no 2 pp 109ndash120 2006

[31] J Rodrıguez-Chueca M I Polo-Lopez R Mosteo M POrmad and P Fernandez-Ibanez ldquoDisinfection of real andsimulated urban wastewater effluents using a mild solar photo-Fentonrdquo Applied Catalysis B Environmental vol 150-151 pp619ndash629 2014

[32] Q Wang S Tian J Long and P Ning ldquoUse of Fe(II)Fe(III)-LDHs prepared by co-precipitationmethod in a heterogeneous-Fenton process for degradation of Methylene Bluerdquo CatalysisToday vol 224 pp 41ndash48 2014

[33] M Siddique R Farooq and G J Price ldquoSynergistic effectsof combining ultrasound with the Fenton process in thedegradation of Reactive Blue 19rdquoUltrasonics Sonochemistry vol21 no 3 pp 1206ndash1212 2014

[34] M Neamtu A Yediler I Siminiceanu and A Kettrup ldquoOxi-dation of commercial reactive azo dye aqueous solutions bythe photo-Fenton and Fenton-like processesrdquo Journal of Pho-tochemistry and Photobiology A Chemistry vol 161 no 1 pp87ndash93 2003

[35] P K Malik and S K Saha ldquoOxidation of direct dyes withhydrogen peroxide using ferrous ion as catalystrdquo Separation andPurification Technology vol 31 no 3 pp 241ndash250 2003

[36] M I Badawy F E Gohary M Y Ghaly and M E MAli ldquoEnhancement of olive mill wastewater biodegradationby homogeneous and heterogeneous photocatalytic oxidationrdquoJournal of Hazardous Materials vol 169 no 1ndash3 pp 673ndash6792009

[37] P V Nidheesh R Gandhimathi and S T Ramesh ldquoDegra-dation of dyes from aqueous solution by Fenton processes areviewrdquo Environmental Science and Pollution Research vol 20no 4 pp 2099ndash2132 2013

[38] W Sabaikai M SekineM Tokumura and Y Kawase ldquoUV lightphoto-Fenton degradation of polyphenols in oolong tea man-ufacturing wastewaterrdquo Journal of Environmental Science andHealth Part A ToxicHazardous Substances and EnvironmentalEngineering vol 49 no 2 pp 193ndash202 2014

[39] W G Li Y Wang and A Irini ldquoEffect of pH and H2

O2

dosageon catechol oxidation in nano-Fe

3

O4

catalyzingUV-Fenton andidentification of reactive oxygen speciesrdquo Chemical EngineeringJournal vol 244 pp 1ndash8 2014

[40] M S Lucas and J A Peres ldquoDegradation of reactive black 5by FentonUV-C and ferrioxalateH

2

O2

solar light processesrdquoDyes and Pigments vol 74 no 3 pp 622ndash629 2007

[41] Y H Zhong X L Liang Y Zhong et al ldquoHeterogeneousUVFenton degradation of TBBPA catalyzed by titanomag-netite catalyst characterization performance and degradationproductsrdquoWater Research vol 46 no 15 pp 4633ndash4644 2012

[42] N Ayten I Arslan-Alaton and T Olmez-Hanci ldquoApplicationof Photo-Fenton-like oxidation for the degradation and detoxi-fication of commercial naphthalene sulfonates a case study withH-acid model pollutantrdquo Desalination and Water Treatmentvol 26 no 1ndash3 pp 139ndash144 2011

[43] D Vujevic S Papic N Koprivanac and A L Bozic ldquoDecol-orization and mineralization of reactive dye by UVFentonprocessrdquo Separation Science and Technology vol 45 no 11 pp1637ndash1643 2010

Submit your manuscripts athttpwwwhindawicom

PainResearch and TreatmentHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom

Volume 2014

ToxinsJournal of

VaccinesJournal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

AntibioticsInternational Journal of

ToxicologyJournal of


StrokeResearch and TreatmentHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Drug DeliveryJournal of



Advances in Pharmacological Sciences

Tropical MedicineJournal of


Medicinal ChemistryInternational Journal of


AddictionJournal of



BioMed Research International

Emergency Medicine InternationalHindawi Publishing Corporationhttpwwwhindawicom Volume 2014


Autoimmune Diseases


Anesthesiology Research and Practice

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of


Pharmaceutics


MEDIATORSINFLAMMATION

of


Microwave electrodeless ultraviolet (MWEUV) was anew-type UV light source developed in recent years [15 16]It includes a mercury vapor lamp powered by microwaveenergy and emitted stable UV radiation The MWEUVlamp would lead to a further development of simple andhigh efficiency photochemical reactor owing to its uniqueadvantages [17ndash19] highUV radiant power long lifetime andbeing immersed into reaction solution with adaptable lampshapes Particularly both UV and microwave radiations areavailable simultaneously by using microwave energy Manystudies have reported successful applications of MWEUVlamp as light source in photolysis [20] UVH

2

O2

[21]and heterogeneous or homogeneous photocatalysis pro-cesses [22ndash24] for organic wastewater treatment It has beenproved that the simultaneous application ofmicrowave powerand UV light exhibits higher efficiency in photochemicalprocesses

In recent years several advanced oxidation processesfor the treatment of pesticide-containing wastewater havebeen proposed However the degradation efficiency forrecalcitrant pesticide substances did not meet the demandof commercial application In this research the MWEUVlamp was employed for enhancing Fenton process to removenonbiodegradable organic pesticide in pesticide-containingeffluent after biotreatment Optimal parameters for CODremoval by the MWEUVFenton process were determinedOxidation degree andmineralization performance of residualpesticide in wastewater were also evaluated in terms ofaverage oxidation state (AOS) carbon oxidation state (COS)DOC and inorganic anions concentration

2 Experimental Methodology

21 Materials and Reagents Fresh wastewater was gener-ated from pesticide container washing process in a chem-ical products estate (Guangdong China) The sequentialprocesses coagulation precipitation and biodegradationhave been employed for elimination of suspended solidsand biodegradable organic substances from the pesticide-containing wastewater Physicalchemical characteristics offresh wastewater and the biotreated wastewater were showedin Table 1 The concentration of COD and pesticides ineffluent wastewater without any advanced treatments stillexceeded the discharge limits imposed by Discharge Limitsof Water Pollutants (Local Standard DB4426-2001)

H2

O2

(30 ww) and FeSO4

sdot7H2

O were prepared ata predetermined concentration as Fenton reagent H

2

SO4

(10mmolL) and NaOH (10mmolL) were used for pHadjustment All chemicals were of analytical grade purchasedfrom Sinopharm Chemical Reagent Co Ltd (ShenzhenChina)

22 Experimental Setup andMethods AU-shapedMWEUVlamp was used in this study The lamp is made by quartztubes filled with 1mg mercury and 066 kPa argon Theexternal diameter is 20mm and effective length is 250mmThe MWEUV lamp had prominent UV emission bands at254 313 365 and 405 nm Microwave generator (Haier Co

Table 1 Physicalchemical characteristics of fresh wastewater andthe biotreated wastewater

Concentration(mgL) Fresh wastewater Effluent after

biological treatmentpH 60sim68

sim70TSS 61885 plusmn 7090

lt15COD 154034 plusmn 20212 1832 plusmn 995BOD5 33658 plusmn 2086

lt15Dimethoate(C5H12NO3PS2)

1566 plusmn 338 1471 plusmn 079

Triazophos(C12H16N3O3PS)

611 plusmn 063 587 plusmn 089

Malathion(C10H19O6PS2)

3165 plusmn 477 2453 plusmn 416

Microwavegenerator

Microwave

Magneticstirrer

MWEUV lamp

Glass reactor

Solution

Sealing flange

Pump

Cooling water inlet

Cooling wateroutlet

Thermometer

Sampling port

Figure 1 Schematic diagram of experimental setup

Ltd China) was operated with 80W output at frequency of245GHzThe output power ofMWEUV lampwasmeasuredby monitoring the temperature of the solution with andwithout the MWEUV lamp [25] According the calculationapproximate 40Wwas supplied to excite MWEUV lamp andthe rest power was consumed or converted to heat

Schematic diagram of the experimental setup is shown inFigure 1 1000mL pesticide-containingwastewater was addedin the glass cylindrical reactor (available capacity of 1000mL)Then required dosage of Fenton reagent was added intothe solution and mixed by a magnetic stirrer (HJ-3 JingdaInstrument Company China) Microwave generator wasapplied to excited MWEUV lamp emitting UV irradiationduring the reaction Solution temperature during the reactionwas kept constant at 25 plusmn 05∘C by circulating solution to acooler with a pump (DP-60 Seisun pumps Co Ltd China)Samples were withdrawn at predetermined time intervalsand the final pH values were adjusted to lower than 3 beforeanalysis All the runs were triplicated

In this study the experiments were carried out as followsand the results were compared (1) Fenton oxidation run(2) UVFenton run assisted by a commercial UV mer-cury lamp (40W of output CREATOR China) and (3)MWEUVFenton run assisted by MWEUV lamp



3

minus SO4

2minus and PO4




Fe2+ +H2

O2


Fe3+ +H2

O 997888rarr Fe (OH)2+ +H+ (2)

Fe (OH)2+ℎ]997888rarr Fe2+ + ∙OH (3)

H2

O2

ℎ]997888rarr ∙OH + ∙OH (4)


2

O2


0 30 60 90 1200

20

40

60

80

COD

rem

oval

()

Time (min)



2

O2



2

O2

systems [25 27 28]


2

O]6


2

O]5


[H2

O]4


33 Effect of H2

O2

Dosage Effect of H2

O2



2 4 6 8 10

40

50

60

70

80CO

D re

mov

al (

)

Initial pH value

(a)

20 40 60 80 100 12010

20

30

40

50

60

70

80

COD

rem

oval

()

H2O2 dosage (mmolL)

(b)

00 02 04 06 08 10

40

50

60

70

80

COD

rem

oval

()

Fe2+ dosage (mmolL)

(c)


O2


O2


O2


the increase of H2

O2


2

O2


2

O2


2

O2


2

O2


2


2

O2


H2

O2


∙ +H2

O (5)HO2

∙ +OH 997888rarr H2

O +O2

(6)

∙OH + ∙OH 997888rarr H2

O2

(7)


O4


O2


2

O2


O2


2

O2


2

O2







2

O2



minus ln119862119905

119862

0

= 119896119905 (9)

where 119862119905


0


119905

119862

0




DOC119905

) (10)


DOC0

) (11)

where COD119905


119905


0


2


4



0 30 60 90 12000

05

10

15

20

t (min)

minusln

(CtC0)


2

O2


0 1 2 3 4 5 6 7 820406080

100120140160180200

COD

conc

entr

atio

n(m

gL)

Time (h)

20253035404550

DO

C co

ncen

trat

ion

(mg

L)


2

O2





0 1 2 3 4 5 6 7 8minus3

minus2

minus1

0

1

2

3AO

S C

OS

Time (h)

AOSCOS


2

O2


2426

2220181614121086420

Con

cent

ratio

n (m

gL)

060

120180

240


Dimethoate

Malathion


O2



3

minus SO4

2minusand PO

4


2minus andPO4


0 30 60 90 120 150 180 210 2400

20

40

60

140

160

Con

cent

ratio

n (m

gL)

Time (min)

NO3minus

SO42minus

PO43minus


2

O2


4 Conclusions


2

O2




Acknowledgment


References















2

O2



2

O2







2




2

O2



2

O2



2





2

H2






2

O2















O2


3

O4



2

O2









Volume 2014

ToxinsJournal of

VaccinesJournal of















AddictionJournal of






Autoimmune Diseases




Journal of


Pharmaceutics



of



3

minus SO4

2minus and PO4




Fe2+ +H2

O2


Fe3+ +H2

O 997888rarr Fe (OH)2+ +H+ (2)

Fe (OH)2+ℎ]997888rarr Fe2+ + ∙OH (3)

H2

O2

ℎ]997888rarr ∙OH + ∙OH (4)


2

O2


0 30 60 90 1200

20

40

60

80

COD

rem

oval

()

Time (min)



2

O2



2

O2

systems [25 27 28]


2

O]6


2

O]5


[H2

O]4


33 Effect of H2

O2

Dosage Effect of H2

O2



2 4 6 8 10

40

50

60

70

80CO

D re

mov

al (

)

Initial pH value

(a)

20 40 60 80 100 12010

20

30

40

50

60

70

80

COD

rem

oval

()

H2O2 dosage (mmolL)

(b)

00 02 04 06 08 10

40

50

60

70

80

COD

rem

oval

()

Fe2+ dosage (mmolL)

(c)


O2


O2


O2


the increase of H2

O2


2

O2


2

O2


2

O2


2

O2


2


2

O2


H2

O2


∙ +H2

O (5)HO2

∙ +OH 997888rarr H2

O +O2

(6)

∙OH + ∙OH 997888rarr H2

O2

(7)


O4


O2


2

O2


O2


2

O2


2

O2







2

O2



minus ln119862119905

119862

0

= 119896119905 (9)

where 119862119905


0


119905

119862

0




DOC119905

) (10)


DOC0

) (11)

where COD119905


119905


0


2


4



0 30 60 90 12000

05

10

15

20

t (min)

minusln

(CtC0)


2

O2


0 1 2 3 4 5 6 7 820406080

100120140160180200

COD

conc

entr

atio

n(m

gL)

Time (h)

20253035404550

DO

C co

ncen

trat

ion

(mg

L)


2

O2





0 1 2 3 4 5 6 7 8minus3

minus2

minus1

0

1

2

3AO

S C

OS

Time (h)

AOSCOS


2

O2


2426

2220181614121086420

Con

cent

ratio

n (m

gL)

060

120180

240


Dimethoate

Malathion


O2



3

minus SO4

2minusand PO

4


2minus andPO4


0 30 60 90 120 150 180 210 2400

20

40

60

140

160

Con

cent

ratio

n (m

gL)

Time (min)

NO3minus

SO42minus

PO43minus


2

O2


4 Conclusions


2

O2




Acknowledgment


References















2

O2



2

O2







2




2

O2



2

O2



2





2

H2






2

O2















O2


3

O4



2

O2









Volume 2014

ToxinsJournal of

VaccinesJournal of















AddictionJournal of






Autoimmune Diseases




Journal of


Pharmaceutics



of


2 4 6 8 10

40

50

60

70

80CO

D re

mov

al (

)

Initial pH value

(a)

20 40 60 80 100 12010

20

30

40

50

60

70

80

COD

rem

oval

()

H2O2 dosage (mmolL)

(b)

00 02 04 06 08 10

40

50

60

70

80

COD

rem

oval

()

Fe2+ dosage (mmolL)

(c)


O2


O2


O2


the increase of H2

O2


2

O2


2

O2


2

O2


2

O2


2


2

O2


H2

O2


∙ +H2

O (5)HO2

∙ +OH 997888rarr H2

O +O2

(6)

∙OH + ∙OH 997888rarr H2

O2

(7)


O4


O2


2

O2


O2


2

O2


2

O2







2

O2



minus ln119862119905

119862

0

= 119896119905 (9)

where 119862119905


0


119905

119862

0




DOC119905

) (10)


DOC0

) (11)

where COD119905


119905


0


2


4



0 30 60 90 12000

05

10

15

20

t (min)

minusln

(CtC0)


2

O2


0 1 2 3 4 5 6 7 820406080

100120140160180200

COD

conc

entr

atio

n(m

gL)

Time (h)

20253035404550

DO

C co

ncen

trat

ion

(mg

L)


2

O2





0 1 2 3 4 5 6 7 8minus3

minus2

minus1

0

1

2

3AO

S C

OS

Time (h)

AOSCOS


2

O2


2426

2220181614121086420

Con

cent

ratio

n (m

gL)

060

120180

240


Dimethoate

Malathion


O2



3

minus SO4

2minusand PO

4


2minus andPO4


0 30 60 90 120 150 180 210 2400

20

40

60

140

160

Con

cent

ratio

n (m

gL)

Time (min)

NO3minus

SO42minus

PO43minus


2

O2


4 Conclusions


2

O2




Acknowledgment


References















2

O2



2

O2







2




2

O2



2

O2



2





2

H2






2

O2















O2


3

O4



2

O2









Volume 2014

ToxinsJournal of

VaccinesJournal of















AddictionJournal of






Autoimmune Diseases




Journal of


Pharmaceutics



of





2

O2



minus ln119862119905

119862

0

= 119896119905 (9)

where 119862119905


0


119905

119862

0




DOC119905

) (10)


DOC0

) (11)

where COD119905


119905


0


2


4



0 30 60 90 12000

05

10

15

20

t (min)

minusln

(CtC0)


2

O2


0 1 2 3 4 5 6 7 820406080

100120140160180200

COD

conc

entr

atio

n(m

gL)

Time (h)

20253035404550

DO

C co

ncen

trat

ion

(mg

L)


2

O2





0 1 2 3 4 5 6 7 8minus3

minus2

minus1

0

1

2

3AO

S C

OS

Time (h)

AOSCOS


2

O2


2426

2220181614121086420

Con

cent

ratio

n (m

gL)

060

120180

240


Dimethoate

Malathion


O2



3

minus SO4

2minusand PO

4


2minus andPO4


0 30 60 90 120 150 180 210 2400

20

40

60

140

160

Con

cent

ratio

n (m

gL)

Time (min)

NO3minus

SO42minus

PO43minus


2

O2


4 Conclusions


2

O2




Acknowledgment


References















2

O2



2

O2







2




2

O2



2

O2



2





2

H2






2

O2















O2


3

O4



2

O2









Volume 2014

ToxinsJournal of

VaccinesJournal of















AddictionJournal of






Autoimmune Diseases




Journal of


Pharmaceutics



of


0 1 2 3 4 5 6 7 8minus3

minus2

minus1

0

1

2

3AO

S C

OS

Time (h)

AOSCOS


2

O2


2426

2220181614121086420

Con

cent

ratio

n (m

gL)

060

120180

240


Dimethoate

Malathion


O2



3

minus SO4

2minusand PO

4


2minus andPO4


0 30 60 90 120 150 180 210 2400

20

40

60

140

160

Con

cent

ratio

n (m

gL)

Time (min)

NO3minus

SO42minus

PO43minus


2

O2


4 Conclusions


2

O2




Acknowledgment


References















2

O2



2

O2







2




2

O2



2

O2



2





2

H2






2

O2















O2


3

O4



2

O2









Volume 2014

ToxinsJournal of

VaccinesJournal of















AddictionJournal of






Autoimmune Diseases




Journal of


Pharmaceutics



of













2

O2



2

O2







2




2

O2



2

O2



2





2

H2






2

O2















O2


3

O4



2

O2









Volume 2014

ToxinsJournal of

VaccinesJournal of















AddictionJournal of






Autoimmune Diseases




Journal of


Pharmaceutics



of












O2


3

O4



2

O2









Volume 2014

ToxinsJournal of

VaccinesJournal of















AddictionJournal of






Autoimmune Diseases




Journal of


Pharmaceutics



of





Volume 2014

ToxinsJournal of

VaccinesJournal of















AddictionJournal of






Autoimmune Diseases




Journal of


Pharmaceutics



of

research article advanced treatment of pesticide...

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