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201716·176·(410128)[]pHCd2+[]Cd2+[]TQ[]A[]1007-1865(2017)16-0176-03RemovalofHeavyMetalCadmiumFromSyntheticWastewaterUsingElectroreductionMethodXiongChangqi,LiuNianhui,WuYaoyi,YangHengmiao,LeiMing(SchoolofEnvironment,HunanAgriculturalUniversity,ChangSha410128,China)Abstract:Treatingwastewatercontainingcadmiumionbyelectroreductionmethodhadbeeninvestigatedinthisarticle.Inthisexperiment,basedontheanalysisofelectrochemicalmechanism,thebestelectrolysistime,thebestelectrolysisvoltageandthepHvalueofthesolutionhadbeendeterminedaccordingtosolutionproperty.Lastlytheremovalrateofcadmiumionhadbeenstudiedthoroughlyunderdifferentionicstrength.Theoptimumtechnologicalconditionsoftheexperimenthadbeendefined.Keywords:electrolyticmethodwastewaterheavymentalCd2+removalrate1CdOH+HCdO2-[1][2-4]0.003mg/L[5][6][7],0.005mg/L90%[8],[9]105mg/L(5×10-3mg/L5mg/L[10-11])[12][13][14][15][16]30[17]Cd2+Cd2+Cd2+,22.12.5LCdCl2·2.5H2ONaOHHCl2.2,,7cm18cm2.5L5cm,10cm×20cm2.0L(:0~60V0~5A)11Fig.1Schemicdiagramofexperimentalsetup2.3Cd2+Cd2+CdCdH2OCl-H2O(l)–2e-→1/2O2(g)+2H+(aq)2Cl-(aq)–2e-→Cl2(g)Cd2+CdCd2+(aq)+2e-→Cd(s)2.4(CdCl2·2.5H2O)Cd2+pHPHS-3CICP-OES:(Optima8300,PerkinElmer,USA)Cd2+2.4.1Cd2+ρ0=4mg/L6h30min0.5h1.0h1.5h2.0h2.5h3.0h3.5h4.0h4.5h5.0h5.5h6.0h[]2017-05-18[](SCX1619)[](1996-)20171644354·177·2.4.2Cd2+ρ0=4mg/L40V0.5h1h1.5h2.0h2.5h3.0h3.5h4.0h4.5h5.0h5.5h6h30min2.4.3pHCd2+ρ0=4mg/Lt=2hU=30V40V50VT=25pH:567892.4.4Cd2+ρ0=0.002mol/L0.004mol/L0.008mol/L0.0050.010.02t=120minU=30V40V50VT=25pH6.533.1Cd2+226h0.5h1.0h1.5hCd2+93.83%(50V)99.08%(50V)99.05%(50V)2.0h2.5h3.0h3.5h4.0h4.5h5.0h5.5h6.0hCd2+99.75%(40V)99.15%(40V)98.48%(50V)98.28%(50V)97.60%(30V)97.25%(30V)96.83%(30V)96.38%(20V)96.33%(20V)Cd2+Cd2+[18]Cd2+Cd2+Cd50V6hCd2+95.48%20V6hCd2+96.33%Cd2+Cd2+Cd2+40V3ACd2+95.60%2Cd2+6hFig.2RemovalrateofheavymetalCd2+inwaterunderdifferentvoltagesafter6h3.2Cd2+ρ0=4mg/L40V0.5%1%1.5%2.0%2.5%3.0%3.5%4.0%4.5%5.0%5.5%6%30min40VCd2+Cd2+3Cd2+440V2hCd2+Cd2+pHCdCd2+Cd2+2h340V6hCd2+Fig.3TrendchartofheavymetalCd2+inwaterunder40voltageafter6h440V6hCd2+Fig.4RemovalrateofheavymetalCd2+inwaterunder40voltageafter6h3.3pHpH11pHTab.1variationsofpHinthewaterunderelectrochemicaltreatmentpHpH30V40V50V55.475.565.6565.555.635.9375.775.906.1686.486.516.8596.796.827.012pHCd2+Tab.2RemovalrateofheavymetalsCd2+inwaterunderdifferentpHpHCd2+/%30V40V50V583.8584.9584.60692.4094.5596.95797.4399.6899.10897.3099.6599.05996.9399.4598.68201716·178·=5Cd2+pH=6Cd2+pH=7Cd2+pH=8Cd2+pH=9Cd2+pHCd2+Cd2+OH-Cd2+H+OH-Cd2+Cd2+Cd2+[19]H+Cd2+Cd2+pHpH=6.0~7.03.43Cd2+Tab.3RemovalrateofheavymetalsinwaterunderdifferentionicstrengthCd2+/%30V40V50V0.00593.6583.4378.200.0195.4996.9397.700.0296.0897.1398.353Cd2+Cd2+0.005Cd2+0.01Cd2+30%40%50%Cd2+0.02Cd2+30%40%50%Cd2+Cd2+Cd2+[20-22]Cd2+OH-OH-,H+Cd2+Cd2+3.510min99%40V2h3A0.6/2L4mg/LCd0.2884(1)40V3ACd2+95.60%(2)Cd2+Cd2+40V2h(3)pHCd2+pHCd2+pHCdCd2+(4)Cd2+Cd2+Cd2+Cd2+Cd2+Cd2+(5)40V2hCd2+[1][J]201332(6)15-17[2][J]201230(1)111-115[3][J]2011(s1)289-293[4][J]2012(s2)101-104[5]AgencyEP2002Editionofthedrinkingwaterstandardsandhealthadvisories[J]EnvironmentalProtectionAgency2002[6]GB5749-2006[M]2007[7][J]2002(6)8-9[8][J]2014(6)46-52[9][J]1993(3)38-42[10][J]1998(6)30-33[11]RajeshwarKIbanezJGSwainGMElectrochemistryandEnvironment[J]JournalofAppliedElectrochemistry199424(11)1077-1091[12]ButterTJEvisonLMHancockICetalRemovalandrecoveryofcadmiumfromdiluteaqueousstreamsbybiosorptionelutionandelectrolysis[J]1995[13]OscarPTHEORYANDPRACTICEOFTHEREMOVALOFHEAVY-METALIONSBYTHEIRPRECIPITATIONASFERRITE-TYPECOMPOUNDSFROMAQUEOUSSOLUTIONATAMBIENTTEMPERATURE[J]MetallurgicalReviewofMmij200117(2)137-179[14]ApiratikulRPavasantPBatchandcolumnstudiesofbiosorptionofheavymetalsbyCaulerpalentillifera[J]BioresourceTechnology200899(8)2766-2777[15]CavacoSAFernandesSQuinaMMetalRemovalofchromiumfromelectroplatingindustryeffluentsbyionexchangeresins[J]JournalofHazardousMaterials2007144(3)634-638[16]LeeHIJungYKimSetalPreparationandapplicationofchelatingpolymer–mesoporouscarboncompositeforcopper-ionadsorption[J]Carbon200947(4)1043-1049[17]ArmstrongRDToddMAtkinsonJWetalSelectiveelectrodepositionofmetalsfromsimulatedwastesolutions[J]JournalofAppliedElectrochemistry199626(4)379-384[18][J]200925(16)6-10[19][J]201030(2)86-88[20][J]201432(3)54-54[21]··[J]201434(10)2547-2551[22][J]200320(1)7-10