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R2=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。
Dodecyl trimethyl ammonium chloride (DTAC) modified attapulgite was prepared via ultrasonic agitation method,and the adsorption behavior of DTAC-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 (R2=0.9999).And Langmuir model was found to be applicable to the prediction of isothermal adsorption (R2>0.98),revealing the adsorption was monolayer.The thermodynamic experimental results showed that the adsorption was a spontaneous,exothermic and entropy-reduction process.
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基金资助
国家自然科学基金(51408397);山西省自然科学基金(201601D102013)
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