蒙脱土和高岭土对Pb^(2+)的吸附  

Sorption of Pb^(2+) on Montmorillonite and Kaolinite

作　　者：张树芹[1] 路福绥[1] 李丽芳[1] 孙停停[1] 

机构地区：[1]山东农业大学化学与材料科学学院,泰安271018

出　　处：《应用化学》2011年第12期1441-1447,共7页Chinese Journal of Applied Chemistry

基　　金：国家重大基础研究("九七三")计划(2004CB418504);2008年省博士基金(2008BS07016);山东农业大学青年创新基金(23621)资助项目

摘　　要：选择带结构负电荷的蒙脱土和带微量结构负电荷的高岭土,研究了其对Pb2+的吸附性能,并探讨了吸附机理。研究表明,蒙脱土和高岭土吸附Pb2+的动力学曲线符合准二级动力学方程,吸附等温线符合Langmuir方程。Pb2+同时以内层配合和外层配合形式吸附,其相对量与pH值有关。在pH值小于4和大于8的范围内,以内层配合物为主;而pH值在4～8范围内外层配合物比例增大。Pb2+能进入蒙脱土的层间,而不能进入高岭土的层间;部分Pb2+可进入黏土颗粒的微孔中被固定。蒙脱土对Pb2+的吸附能力和饱和吸附量明显高于高岭土。Sorption activities of Pb2＋ on montmorillonite and kaolinite were studied and a sorption mechanism was proposed.The sorption kinetics and the sorption isotherms of Pb2＋ on montmorillonite and kaolinite can be described by the pseudo-second-order kinetics and Langmuir isotherm respectively.The sorption mechanism of Pb2＋ on the montmorillonite and kaolinite is the surface complex mechanism,simultaneously forming inner-sphere surface complexes and outer-sphere surface complexes.The relative content of inner（or outer）-sphere surface complexes is pH dependent and is dominant beyond（or within） the pH range of 4~8,respectively.The sorption amount in mg/g of Pb2＋ on montmorillonite is obviously higher than that on kaolinite.The affinity of montmorillonite for Pb2＋ is higher than that of kaolinite for Pb2＋.

关 键 词：蒙脱土 高岭土 PB2+ 吸附机理 

分 类 号：O647[理学—物理化学]