两性修饰膨润土对苯酚吸附的动力学研究

以两性表面活性剂十八烷基二甲基甜菜碱(BS-18)为修饰剂,制得两性修饰膨润土,研究了不同修饰比例、温度及pH值等条件下,两性修饰土对苯酚的吸附反应和动力学特征,并对吸附机制进行探讨。结果表明,不同修饰比例的两性修饰土对苯酚的吸附速度参数均大于未修饰膨润土,且均随着修饰比例的增加而增大,表明修饰可以显著加快膨润土对苯酚的吸附速率;低温有利于吸附;吸附量在pH 4~8的范围内较稳定,pH大于8后,吸附量迅速降低。两性修饰土对苯酚的吸附动力学曲线符合伪二级动力学模型。

Adsorption kinetics of phenol on bentonite modified with BS-18

The characteristics of adsorption kinetics of phenol on Octadecane-Betaine(BS-18) modified bentonite along with the adsorption mechanism were investigated at different conditions of modification ratio,temperature and pH.The results showed that the adsorption velocity parameter of phenol on modified bentonite was greater than that on unmodified bentonite,and increased with the increase of modification ratio,indicating that the adsorption velocity of the bentonite to phenol could be accelerated significantly by BS-18 modification.Phenol adsorption was faster at low temperature,and varied little in pH 4～8,while it declined rapidly beyond pH 8.Pseudo-second-order kinetic model was the best to describe phenol adsorption kinetic curve on BS-18 modified bentonite.