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Adsorption of Pb2+, Cd2+ and Sr2+ ions onto natural and acid-activated sepiolites
dc.creator | Lazarević, Slavica | |
dc.creator | Janković-Častvan, Ivona | |
dc.creator | Jovanović, Dušan | |
dc.creator | Milonjić, Slobodan K. | |
dc.creator | Janaćković, Đorđe | |
dc.creator | Petrović, Rada | |
dc.date.accessioned | 2021-03-10T10:47:35Z | |
dc.date.available | 2021-03-10T10:47:35Z | |
dc.date.issued | 2007 | |
dc.identifier.issn | 0169-1317 | |
dc.identifier.uri | http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1157 | |
dc.description.abstract | The 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.publisher | Elsevier Science Bv, Amsterdam | |
dc.relation | info:eu-repo/grantAgreement/MESTD/MPN2006-2010/142070/RS// | |
dc.rights | restrictedAccess | |
dc.source | Applied Clay Science | |
dc.subject | sepiolite | en |
dc.subject | acid treatment | en |
dc.subject | adsorption | en |
dc.subject | heavy metals | en |
dc.subject | Sr2+ ion | en |
dc.title | Adsorption of Pb2+, Cd2+ and Sr2+ ions onto natural and acid-activated sepiolites | en |
dc.type | article | |
dc.rights.license | ARR | |
dc.citation.epage | 57 | |
dc.citation.issue | 1-2 | |
dc.citation.other | 37(1-2): 47-57 | |
dc.citation.rank | M21 | |
dc.citation.spage | 47 | |
dc.citation.volume | 37 | |
dc.identifier.doi | 10.1016/j.clay.2006.11.008 | |
dc.identifier.scopus | 2-s2.0-34249782855 | |
dc.identifier.wos | 000247776100005 | |
dc.type.version | publishedVersion |