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Adsorption of Pb2+, Cd2+ and Sr2+ ions onto natural and acid-activated sepiolites
dc.creator | Lazarevic, Slavica | |
dc.creator | Jankovic-Častvan, Ivona | |
dc.creator | Jovanovic, Dusan | |
dc.creator | Milonjić, Slobodan K. | |
dc.creator | Janaćković, Đorđe T. | |
dc.creator | Petrović, Rada | |
dc.date.accessioned | 2018-03-01T20:05:08Z | |
dc.date.available | 2018-03-01T20:05:08Z | |
dc.date.issued | 2007 | |
dc.identifier.issn | 0169-1317 | |
dc.identifier.uri | https://vinar.vin.bg.ac.rs/handle/123456789/3206 | |
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. (C) 2006 Elsevier B.V. All rights reserved. | en |
dc.rights | restrictedAccess | en |
dc.source | Applied Clay Science | en |
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 | en |
dcterms.abstract | Јанковиц-Цастван, Ивона; Јовановиц, Дусан; Јанацковиц, Дјордје; Петровиц, Рада; Лазаревиц, Славица; Милоњић Слободан; | |
dc.citation.volume | 37 | |
dc.citation.issue | 1-2 | |
dc.citation.spage | 47 | |
dc.citation.epage | 57 | |
dc.identifier.wos | 000247776100005 | |
dc.identifier.doi | 10.1016/j.clay.2006.11.008 | |
dc.citation.rank | M21 | |
dc.identifier.scopus | 2-s2.0-34249782855 |
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