不同电解质体系中土壤胶体凝聚动力学的动态光散射研究朱华玲

[Article](WuliHuaxueXuebao)ActaPhys.-Chim.Sin.,2009,25(6)1225-1231JuneReceived:December8,2008;Revised:March12,2009;PublishedonWeb:April16,2009.*Correspondingauthor.Email:[e-mail];Tel:[phone].(40371061)(KJ050205)鬁EditorialofficeofActaPhysico-ChimicaSinica*(,400716)KNO3Mg(NO3)2.:(1),;(2),;(3),Mg(NO3)2KNO3.,,,(CFC),CFC.;;;;O648DynamicLightScatteringStudyontheAggregationKineticsofSoilColloidalParticlesinDifferentElectrolyteSystemsZHUHua-LingLIBingXIONGHai-LingLIHang*JIAMing-Yun(CollegeofResourceandEnvironment,SouthwestUniversity,Chongqing400716,P.R.China)AbstractSoilcolloidalaggregationkineticswasstudiedatdifferentconcentrationsofKNO3andMg(NO3)2bydynamiclightscattering.Byanalyzingthechangeinlightintensityandeffectivediameterofaggregateswithtime,weconcludethat:(1)ThestabilityofthelightintensityinanaggregationprocessisabasisforjudgingifthecollisionisdominatedeitherbyBrownforceorgravity;(2)Withdifferentelectrolytesystems,soilcolloidalaggregationexhibitsafastdiffusion-limitedclusteraggregation(DLCA)characterorvariousslowreactionlimitedclusteraggregation(RLCA)charactersandagravitysensingelectrolyteconcentrationexistsinRLCA;(3)TheaggregationcharactersinducedbytwoelectrolytesareessentiallysimilarbuttheaggregatingprocessismoresensitivetotheMg(NO3)2electrolyteconcentrationchangethantoKNO3.Byanalyzingthechangeofaverageaggregationvelocitywithelectrolyteconcentration,theturningpointwhereelectrolyteconcentrationchangesfromslowtofastaggregationisdesignatedasthecriticalflocculationconcentration(CFC).AnewmethodformeasuringtheCFCexperimentallyisthusprovided.KeyWordsDynamiclightscattering;Soilcolloid;Fastaggregation;Slowaggregation;Kinetics,DLVO[1].,,,.、、,.,,,.,.1225ActaPhys.-Chim.Sin.,2009Vol.25,()0-1[2],:(DLCA)[3-5];(RLCA)[5].,,1,DLCA;,,1,RLCA.、.[6,7];(、)[7-9].DLCA,[3,7];RLCA[3,7].,,,,[8].,[7-12],:、、,..,、、、[13-15],,、、.Derrendinger[13]“-NaCl”,,DLCARLCA,、、DLCARLCA.Adachi[14]NaClpH.,.0.001mm,、,,.()()[16,17].,,,.,,.,、.11.1K+,———,pH3.8.KOH,,0.2μm,.HNO3,,,.KOHpH=8.3,,,K+.K+K+2.375×10-5mol·L-1.0.95g·L-1,0.475g·L-1.2min,.0、9、18、27、45、90、180mmol·L-1KNO3;0.00、0.09、0.145、0.18、0.45、1.80、4.50mmol·L-1Mg(NO3)2..Li[18-20],φ0κ-1(1).1.2,,(ACF),(Eff.diam)(Poly).[9,21,22].,..,2.5μm[13].Blookhaven1226No.6/,BI-200SM,BI-9000AT.15mW,532nm.90°1h.20min,25℃.10mL,(150±10)nm,1mL.,30s、.22.11、.,,100min;,:Mg(NO3)20.09、0.145mmol·L-1KNO39、18mmol·L-1,,;Mg(NO3)20.18-4.50mmol·L-1KNO327-180mmol·L-1,,.,Mg(NO3)20.45-4.50mmol·L-1KNO345-180mmol·L-1,(Mg(NO3)20-16min,KNO30-23min)..,,,;,,,(),,.,,;,,,,,.,,,,,“”[23],,1Table1Electrochemicalpropertiesofyellowearthcolloidindifferenttypesandconcentrationsofelectrolytesφ0issurfacepotential,κ-1isthicknessofdiffusedoublelayer.c(KNO3)/(mmol·L-1)φ0/Vκ-1/nmc(Mg(NO3)2)/(mmol·L-1)φ0/Vκ-1/nm0-0.2623199.240.00-0.2623199.249-0.161410.2350.09-0.119818.68518-0.14967.2370.145-0.115714.72127-0.14275.9090.18-0.113913.21245-0.13404.5770.45-0.10618.35690-0.12223.2371.80-0.09434.178180-0.11052.2894.50-0.08652.6421Fig.1Variationofscatteredlightintensitywithtimeinaggregationprocessesforyellowearthcolloidindifferenttypesandconcentrationsofelectrolytes1227ActaPhys.-Chim.Sin.,2009Vol.25,.,.,,,.2.22,.,.Mg(NO3)20.45-4.50mmol·L-1KNO345-180mmol·L-1,,:(1);(2)Mg(NO3)22.0μm,KNO31.7μm;(3),Mg(NO3)20-16min,KNO30-23min,(1).,DLCA,.DLVO,,[9],,1,DLCA.,DLCA[9,14].,(1),,,...(2)“-”(1),,.DLCA、,(2.0μm),.,.KNO39-27mmol·L-1Mg(NO3)20.09-0.18mmol·L-1,,.,,.,,,(1),DLCARLCA.,RLCA,,.2,,DLCA,,RLCA,,[3,5,7,14].,(1),0.18mmol·L-1Mg(NO3)2272(y)Fig.2Growthofeffectivediameter(y)ofaggregatesforyellowearthcolloidindifferenttypesandconcentrationsofelectrolytes1228No.6mmol·L-1KNO3,(Mg(NO3)20-30min,KNO30-45min)(,DLCA),,,.Mg(NO3)20.145mmol·L-1、KNO318mmol·L-1,,.,,.,,,,.,,.Mg(NO3)20.145mmol·L-1、KNO318mmol·L-1,.,RLCA,Mg(NO3)20.145mmol·L-1,KNO318mmol·L-1.[24].2.3.,v=ZABe-△ERT(1),e-△ERT,()△E,ZAB().,ZAB,v.,(),.,,v.,3.3,.v軃:v軃=1t-1t1乙v(t)d(t)(2)(2),3,,.,1,.,K+(199.24nm),,,;Electrolytec/(mmol·L-1)Fittingfunction(y)R2Mg(NO3)24.50563.82lnt+962.650.9194899.3t0.40560.85471.80451.17lnt+960.540.8367842.74t0.37830.75790.45520.08lnt+877.060.8274787.76t0.42120.78880.18366.53t0.35550.99090.1458.7592t+263.250.98320.092.1851t+161.70.9737KNO3180458.67lnt+582.510.9417561.97t0.44640.856490412.81lnt+490.330.9817573.4t0.38220.974845412.13lnt+521.910.9353528.57t0.42540.876627371.83t0.35430.989918198.94t0.28310.972991.67t0.1650.99812Table2EquationfittingofeffectivediameterwithtimeforyellowearthcolloidindifferenttypesandconcentrationsofelectrolytesElectrolytec/(mmol·L-1)Fittingfunction(v(t))R2Mg(NO3)24.501011.4t-0.63690.95411.80966.18t-0.66860.93940.451227t-0.77470.92970.18361.35t-0.64060.99780.145222.6t-0.77330.99760.09146.68t-0.88700.9994KNO3180646.45t-0.60470.914890561.75t-0.60620.987045552.2t-0.59700.927427343.69t-0.61570.997318202.71t-0.73540.99809166.64t-0.83350.99993Table3EquationfittingofaggregationvelocityforyellowearthcolloidindifferenttypesandconcentrationsofelectrolytesR2:correlationcoefficient1229ActaPhys.-Chim.Sin.,2009Vol.253(v軈)Fig.3Averageaggregationvelocity(v軈)