Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5410927 | Journal of Molecular Liquids | 2015 | 7 Pages |
Abstract
The sorption of Cd(II) and U(VI) on sepiolite as a function of contact time, pH, ionic strength, temperature and initial concentration was investigated by batch techniques. The sorption kinetics showed that sorption of Cd(II) and U(VI) on sepiolite can be satisfactorily fitted by pseudo-second order kinetic model with high correlation coefficients of 0.999. The sorption of Cd(II) and U(VI) on sepiolite significantly decreased with increasing ionic strength at pHÂ <Â 4.0, whereas the sorption of Cd(II) and U(VI) on sepiolite was independent of ionic strength at pHÂ >Â 5.0, indicating that cation exchange/outer sphere surface complexation and inner-sphere surface complexation dominated the Cd(II) and U(VI) sorption on sepiolite at pHÂ <Â 4.0 and pHÂ >Â 5.0, respectively. According to surface complexation modeling, the sorption of Cd(II) and U(VI) on sepiolite can be satisfactorily simulated by diffuse double layer model with cation exchange sites (XNa/XH) at low pH and surface complexation sites (SOCd+/SOUO2+) at high pH conditions. The finding presented herein indicated that clay minerals can potentially be served as an efficient retardant for the immobilization of heavy metals and radionuclides in environmental cleanup.
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Authors
Jieying Huang, Zhenwei Wu, Liwei Chen, Yubing Sun,