腐殖酸对无定形氢氧化铝吸附锌的影响

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1、EffectsofhumicacidonZn2+adsorptionindrinkingwater5101520distributionsystemswithamorphousAl(OH)3formation#Abstract:Zinc(Ⅱ)commonlyexistsindrinkingwater.ThispaperaimstoinvestigatetheeffectsofhumicacidontheadsorptionofZn2+onamorphousAl(OH)3.Bothsuspensionandwell

2、scaledformsofAl(OH)3wereinvestigatedapplyingICP-AESdeterminationandVisualMINTEQcalculation.ItwasfoundthatinsolutionswithoutHA,pHhadnotableeffectsontheremovalofZn2+.ChemicaladsorptionmainlytookplaceatpHabove7.5;1.0gsolidcouldaccumulateabout15.9mgZn2+at15℃.Becaus

3、eofH+inhibition,activereactionsitesonamorphousAl(OH)3surfaceweremuchlessatpHbelow7.5.TheadsorptionofZn2+onAl(OH)3changedgraduallyfromchemicalcoordinationtophysicaladsorption.ComparedwithZn2+,theadsorptionofHAonAl(OH)3suspensionwasstrong.IndrinkingwaterwithHAcoe

4、xisting,theadsorptionofZn2+wasenhancednotably;whilepHhadlittleeffectsitsremoval.UnderthebridgingeffectsofHA,Zn2+couldnotbedetectedinsolutionwithHAabove1.0mg/L,muchlowerthanthestandardrequiredlevel.TheadsorptionofAl(OH)3scaleforZn2+wasweak,about0.2mg/g.Betterman

5、agementonsedimentaccumulationandZn2+preservationwassuggestedtocontroltheconcentrationofZn2+residual.Keywords:aluminumhydroxide;drinkingwater;humicacid;pipescale250IntroductionZincwascommonlyfoundindrinkingwatersuppliesandessentialforhumanhealth[1-3].However,exc

6、essiveconcentrationsofZn2+couldresultinmetallictastingwater,reducedwaterpressureandflowinthepipesfromtheaccumulationofzinc-containingsedimentsandhuman30354045healthproblems[4-6].Leone(2006)foundthatexcessiveintakeofZn2+couldincreasetherisksofcancerandcardiovas

7、cularmortality[7].AlthoughveryfewnaturalwaterscontainedZn2+atlevelssufficienttocauseacutehealtheffects,somewaterseithertreatedoruntreatedhavechemicalcharacteristicsthatallowthemtomobilizeZn2+frompipematerials[8,9].Manygovernmentshaddevelopedregulationstoensuret

8、hedrinkingwatersecurity;thelimitvalueinChinais1.0mg/L(GB5749-2006).IthadbeenthoughtthattheconcentrationofZn2+maintainsconstantaswaterpassedthroughwaterdistributionsystems[10