超声法十二烷基三甲基氯化铵改性凹凸棒土对水中苯酚的吸附行为研究

Research of adsorption behavior for phenol in water on DTAC-modified-attapulgite via ultrasonic method

采用超声搅拌法,制备十二烷基三甲基氯化铵(DTAC)改性的凹凸棒土,探讨了改性后的DTAC-凹凸棒土对水中苯酚的吸附行为。对比了超声搅拌和机械搅拌这两种工艺在DTAC改性凹凸棒土过程中的作用;优化超声搅拌时间和DTAC/凹凸棒土的用量配比,通过正交试验得到其最佳值分别为9min和40mmol/100g。采用优化改性的DTAC-凹凸棒土对水中苯酚进行吸附研究,结果表明,超声改性的DTAC-凹凸棒土比未改性凹凸棒土的吸附量最多可提高近12倍;碱性条件有利于苯酚的吸附;DTAC-凹凸棒土对苯酚的吸附是一个快速过程,5min即可达到最大吸附容量的80%,动力学过程符合准二级动力学模型,线性相关系数R^2=0.9999;吸附等温线符合Langmiur等温吸附模型(R2>0.98),说明该吸附以单层吸附为主;热力学结果表明,该行为是一个自发的、放热的、熵减少的吸附过程。

Dodeeyl trimethyl ammonium chloride （DTAC） modified attapulgite was prepared via ultrasonic agitation method,and the adsorption behavior of DTA@attapulgite for phenol in water was discussed.As comparison, mechanical mixing method was investigated as well. The ultrasonic time and dosage ratio of DTAC/attapulgite were also optimized by orthogonal experiment, which were 9min and 40mmol/100g respectively.The results showed that the adsorption capacity of DTAC-attapulgite could be improved twelve times compared with the natural attapulgite. The adsorption process was proved to be a fast process, and the adsorption capacity could reach 80% of maximum adsorption capacity within 5 minutes.Besides, the adsorption process could be well described by the pseudo-second order kinetic model （R^2 =0. 9999）.And Langmuir model was found to be applicable to the prediction of isothermal adsorption （R^2〉 0.98）, revealing the adsorption was monolayer. The thermodynamic experimental results showed that the adsorption was a spontaneous,exothermic and entropy-reduction process.