Authors: Qiaohui Fan Ping Li Zhong Zheng Wangsuo Wu Chunli Liu
Publish Date: 2013/11/08
Volume: 299, Issue: 3, Pages: 1767-1775
Abstract
The sorption species of EuIII on γAl2O3 and bentonite was investigated by batch surface complexation model SCM and Xray absorption spectroscopy XAS The results showed that sorption edges of EuIII on γAl2O3 and bentonite were as expected shifted forward high pH with the increasing in EuIII concentration and sorption of EuIII was strongly dependent on pH In γAl2O3 system sorption of EuIII was decreased above pH 85 at low concentration of EuIII because of water soluble carbonate species of EuIII however the decline did not appear at high concentration of EuIII possibly due to a offset effect of surface precipitation Actually the sorption species of EuIII on bentonite mainly referred to at least four kinds of species including ion exchange X3Eu0 at low pH innersphere complexes AlOEu2+ and SiOEu2+ at neutral condition and hydrolysis species SiOEuOH 2 0 at alkaline condition Linear combination fitting LCF in k space testified that hydrolysis of EuOH3s and oxide of Eu2O3 species were major for EuIII sorption on γAl2O3 whereas Eu3+aq and hydrolysis species comprised sorption species on bentonite Extended Xray absorption fine structure EXAFS analysis further confirmed the prediction from SCM and LCF In addition the typical shells of Eu–Al in R range of 30–34 Å and Eu–Si at ~40 Å were found in radial structure functions which was possibly identified to edgeshared bidentate of EuIII on Al2O3 and bentoniteThis study was jointly supported by the National Natural Science Foundation of China Grant No 11075006 91026010 Special Foundation for Highlevel Waste Disposal 2007840 2012851 the Fundamental Research Funds for the Central Universities Analysis foundation of Peking University 16–19 and the National Synchrotron Radiation Innovation Foundation of Chinese Education Ministry 20090137S We greatly acknowledge Dr Bo He NSRL USTC for helpful technical assistance of EXAFS experiments
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