有机改性蛭石吸附 U（Ⅵ）的行为及机理研究

摘要

通过静态吸附实验，研究了用十六烷基三甲基溴化铵（HDTMA・Br）改性的蛭石对U（Ⅵ）的吸附行为，以及有机改性蛭石（吸附剂）用量、pH值、铀初始质量浓度、吸附时间等因素对有机改性蛭石吸附U （Ⅵ）效果的影响，从热力学和动力学方面对吸附过程进行了分析，并通过 FT‐IR和SEM 探讨了其相关吸附机理。结果表明：增加吸附剂用量、延长吸附时间和降低铀初始质量浓度都能提高有机改性蛭石对铀的去除率，最佳吸附pH值为6.5左右，120 min达到吸附平衡；用絮凝剂协同吸附能提高有机改性蛭石对铀的吸附效果；有机改性蛭石对铀的吸附遵循 Langmuir吸附等温线，符合准二级动力学方程。有机改性蛭石吸附铀前后的FT‐IR表明，—O H、Si O等基团起重要作用；SEM 分析表明，有机改性蛭石吸附U（Ⅵ）引起其形态结构的改变。%The adsorption behavior of U (Ⅵ ) on modified vermiculite by HDTMA ・Br was studied with static experiments .The effects of the amount of adsorbent ,pH ,initial mass concentration of uranium and time on the removal rate of uranium were investiga‐ted .The unit mass of adsorption process was analyzed in thermodynamics and kinetics , and the adsorption mechanism was analyzed with FT‐IR and SEM .The results indicate that the removal rate of uranium can increase with the increase of adsorbent amount and time ,and the decrease of initial mass concentration of uranium .T he adsorption equilib‐rium tends to be achieved in 120 min ,and solution using flocculant and modified vermic‐ ulite can be improved .T he adsorption of uranium by organically modified vermiculite is a complex process ,so Langmuir monolayer adsorption theory and Freundlich adsorption theory cannot fully explain the adsorption process .The removal mechanism of uranium by using modified vermiculite fits Langmuir adsorption law ,and is in line with quasi‐second order kinetic equation .It is confirmed by FT‐IR that —OH and Si O play an important role in the adsorption of uranium .SEM show s that the adsorption of uranium using modified vermiculite causes the structure change .