Adsorption of Pb2+, Cd2+ and Sr2+ ions onto natural and acid-activated sepiolites
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Аутори
Lazarevic, SlavicaJankovic-Častvan, Ivona
Jovanovic, Dusan
Milonjić, Slobodan K.
Janaćković, Đorđe T.
Petrović, Rada
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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 o...f 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.
Кључне речи:
sepiolite / acid treatment / Adsorption / heavy metals / Sr2+ ionИзвор:
Applied Clay Science, 2007, 37, 1-2, 47-57
DOI: 10.1016/j.clay.2006.11.008
ISSN: 0169-1317
WoS: 000247776100005
Scopus: 2-s2.0-34249782855
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Институција/група
VinčaTY - JOUR AU - Lazarevic, Slavica AU - Jankovic-Častvan, Ivona AU - Jovanovic, Dusan AU - Milonjić, Slobodan K. AU - Janaćković, Đorđe T. AU - Petrović, Rada PY - 2007 UR - https://vinar.vin.bg.ac.rs/handle/123456789/3206 AB - 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. T2 - Applied Clay Science T1 - Adsorption of Pb2+, Cd2+ and Sr2+ ions onto natural and acid-activated sepiolites VL - 37 IS - 1-2 SP - 47 EP - 57 DO - 10.1016/j.clay.2006.11.008 ER -
@article{ author = "Lazarevic, Slavica and Jankovic-Častvan, Ivona and Jovanovic, Dusan and Milonjić, Slobodan K. and Janaćković, Đorđe T. and Petrović, Rada", year = "2007", 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.", journal = "Applied Clay Science", title = "Adsorption of Pb2+, Cd2+ and Sr2+ ions onto natural and acid-activated sepiolites", volume = "37", number = "1-2", pages = "47-57", doi = "10.1016/j.clay.2006.11.008" }
Lazarevic, S., Jankovic-Častvan, I., Jovanovic, D., Milonjić, S. K., Janaćković, Đ. T.,& Petrović, R.. (2007). Adsorption of Pb2+, Cd2+ and Sr2+ ions onto natural and acid-activated sepiolites. in Applied Clay Science, 37(1-2), 47-57. https://doi.org/10.1016/j.clay.2006.11.008
Lazarevic S, Jankovic-Častvan I, Jovanovic D, Milonjić SK, Janaćković ĐT, Petrović R. Adsorption of Pb2+, Cd2+ and Sr2+ ions onto natural and acid-activated sepiolites. in Applied Clay Science. 2007;37(1-2):47-57. doi:10.1016/j.clay.2006.11.008 .
Lazarevic, Slavica, Jankovic-Častvan, Ivona, Jovanovic, Dusan, Milonjić, Slobodan K., Janaćković, Đorđe T., Petrović, Rada, "Adsorption of Pb2+, Cd2+ and Sr2+ ions onto natural and acid-activated sepiolites" in Applied Clay Science, 37, no. 1-2 (2007):47-57, https://doi.org/10.1016/j.clay.2006.11.008 . .