Mg-Al型水滑石对水溶液中F-的吸附

采用水热法合成Mg-Al型水滑石(LDHs),研究LDHs及其焙烧产物C-LDHs对水溶液中F-的吸附行为,并用X射线衍射和热重分析对LDHs,C-LDHs以及吸附F-后的C-LDHs(R-LDHs)的结构和性质进行了表征. 结果表明:LDHs对水溶液中的F-基本没有吸附,而C-LDHs对F-有较大的吸附容量,同时,酸性的增强有利于C-LDHs对F-的吸附. C-LDHs对F-吸附4h后可达到吸附平衡. 通过吸附F-,C-LDHs的结构由吸附前的混合氧化物固溶体恢复到层状结构, 表明C-LDHs对水溶液中F-的高吸附性能是因为其具有较强的"记忆效应".

ADSORPTION OF FLUORIDE FROM AQUEOUS SOLUTION BY Mg-Al HYDROTALCITE

In this study,Mg-Al hydrotalcites(LDHs)were prepared by hydrothermal method and the adsorption of fluoride onto the LDHs and its calcined product(C-LDHs)was investigated.XRD and TG were used to characterize the LDHs,C-LDHs and fluoride adsorbed C-LDHs(R-LDHs).Results show that fluoride adsorption onto the LDHs is negligible,while good sorption of fluoride onto the C-LDH is achieved.The fluoride uptake onto the C-LDHs was further enhanced under acidic solution.The study of adsorption kinetics indicated that the adsorption equilibrium of fluoride onto the C-LDH was achieved in 4h.In addition,the structure of C-LDHs shifted to layer structure of LDHs after the fluoride adsorption,indicating that the memory effect of C-LDHs accounted for the effective removal of aqueous fluoride.