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dc.creatorLazarević, Slavica
dc.creatorJanković-Častvan, Ivona
dc.creatorJovanović, Dušan
dc.creatorMilonjić, Slobodan K.
dc.creatorJanaćković, Đorđe
dc.creatorPetrović, Rada
dc.date.accessioned2021-03-10T10:47:35Z
dc.date.available2021-03-10T10:47:35Z
dc.date.issued2007
dc.identifier.issn0169-1317
dc.identifier.urihttp://TechnoRep.tmf.bg.ac.rs/handle/123456789/1157
dc.description.abstractThe adsorption mechanisms of Ph2+, Cd2+ and Sr2+ ions on natural sepiolite and the influence of acid treatment on the adsorption capacity of sepiolite were investigated. The point of zero charge pH(pzc), is 7.4 +/- 0.1 for natural sepiolite and 6.9 +/- 0.1 for partially acid-activated sepiolite. The shift of the pH(pzc) of sepiolites toward lower pH values in solutions of Ph2+ and Cd2+ ions indicates that specific adsorption of these cations on natural and acid-activated sepiolites occurred, which was more pronounced for Pb2+ ions than for Cd2+ ions. There was no shift of the pH(pzc) in Solution containing Sr2+ ions, suggesting that specific adsorption of this cation did not occur. The affinity for ion exchange with the Mg2+ ions from the sepiolite structure was the highest for Pb2+ ions, then Cd2+, whereas the affinity for Sr2+ ions was negligible. The adsorption isotherms suggest that the sequence of the efficiency of the sepiolites adsorption is Ph2+ gt Cd2+ gt Sr2+. The retention of Pb2+ and Cd2+ ions by sepiolite occurs dominantly by specific adsorption and exchange of Mg2+ ions from the sepiolite structure. The concentration in the external outer sphere of the Stem layer by electrostatic forces is the dominant mechanism for the retention of Sr2+ ions on the surface of sepiolites. Despite increases in the surface areas upon acid activation, improvements in the adsorption were not observed, as a result of the decreasing number of Mg-OH groups, as main centers for specific adsorption, and the number of Mg2+ ions available for ion exchange with Pb2+, Cd2+ and Sr2+ ions. The removal of Mg-OH groups from the sepiolite also resulted in a decrease in the point of zero charge and an increase of the relative surface acidity, from 2.6 +/- 0.1 for the natural to 6.4 +/- 0.1 for the acid-activated sepiolite.en
dc.publisherElsevier Science Bv, Amsterdam
dc.relationinfo:eu-repo/grantAgreement/MESTD/MPN2006-2010/142070/RS//
dc.rightsrestrictedAccess
dc.sourceApplied Clay Science
dc.subjectsepioliteen
dc.subjectacid treatmenten
dc.subjectadsorptionen
dc.subjectheavy metalsen
dc.subjectSr2+ ionen
dc.titleAdsorption of Pb2+, Cd2+ and Sr2+ ions onto natural and acid-activated sepiolitesen
dc.typearticle
dc.rights.licenseARR
dc.citation.epage57
dc.citation.issue1-2
dc.citation.other37(1-2): 47-57
dc.citation.rankM21
dc.citation.spage47
dc.citation.volume37
dc.identifier.doi10.1016/j.clay.2006.11.008
dc.identifier.scopus2-s2.0-34249782855
dc.identifier.wos000247776100005
dc.type.versionpublishedVersion


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