粉末活性炭对水中农药甲基托布津吸附动力学和机理

Investigation of Adsorption Kinetics and Mechanism of Thiophanate-Methyl in Water by Powdered Activated Carbon

针对农药甲基托布津排入水体的污染问题,在含有相同浓度甲基托布津的溶液中分别投加竹质、椰壳质和煤质粉末活性炭,置入恒温振荡器进行甲基托布津的吸附实验,并对吸附效果进行对比。筛选出竹质粉末活性炭为吸附去除甲基托布津的最佳炭种。以竹质活性炭为吸附剂和甲基托布津为吸附质,深入开展了吸附速率和吸附动力学以及吸附热力学研究。研究结果表明,对于三种PAC,采用二级动力学模型描述和表达均更为贴切和恰当;Langmuir吸附等温线模型拟合参数,更适合描述竹质PAC吸附甲基托布津,为单分子层的吸附过程,符合理想的单层定位吸附理论机制。

Aiming at the pollution problem of pesticide thiophanate-methyl in water,Bamboo,coconut shell and coal powder activated carbon were added to the solution containing the same concentration of thiophanate-methyl,and a constant temperature oscillator was placed to carry out the adsorption experiment of thiophanate-methyl,and the adsorption effects were compared.The bamboo powder activated carbon was selected as the best carbon species for the adsorption and removal of methyl thiophanate.Taking bamboo activated carbon as adsorbent and thiophanate-methyl as adsorbate,the adsorption rate and adsorption kinetics as well as adsorption thermodynamics studies were carried out in depth.The results show that for the three PACs,the second-order kinetic model description and expression are more relevant and appropriate;the Langmuir adsorption isotherm model fitting parameters are more suitable for describing the bamboo PAC adsorption of thiophanate-methyl,which is a monolayer.The adsorption process conforms to the ideal single-layer positioning adsorption theory mechanism.