软阳离子钾改性蒙脱石矿物对硝基苯的强化吸附实验研究

Experimental research on intensified adsorption of soft K^+ cation-modified montmorillonite mineral for nitrobenzene

考察软阳离子钾改性蒙脱石在K+存在的条件下对硝基苯的强化吸附行为,详细分析比较了Henry和Fre-undlich方程对硝基苯吸附等温线的拟合结果,同时还进行了吸附热力学研究。实验结果表明,软阳离子钾对蒙脱石吸附硝基苯具有强化作用;硝基苯在蒙脱石上的吸附符合Freundlich和Henry方程,两模型方程线性拟合结果的相关系数均在0.96以上。热力学分析结果表明,硝基苯在蒙脱石上的吸附过程是一个自发的放热过程,说明蒙脱石对硝基苯的吸附主要由分配与EDA作用机制所控制。钾离子存在可为硝基苯吸附营造有利场所,不仅改善准入条件,同时增加某些吸附点位,从而促进并强化蒙脱石对硝基苯的吸附。

The sorption behaviors of nitrobenzene（NB） onto the soft K＋ cation modified montmorillonite（K-Mt） under the conditions of adding of K＋ ion and varying reaction temperatures were investigated in this paper.The sorption kinetic experiments showed that the sorption equilibrium of NB could be reached within 8 h.A comparative analysis of the Henry and Freundlich equations was made to evaluate the sorption isotherms of NB onto the K-Mt,and some thermodynamic experiments were conducted to explore the sorption mechanism.The results show that soft cation of K＋ can strengthen the sorption of K-Mt for NB.The adsorption isotherms of NB by the K-Mt can be fitted well with Henry and Freundlich equation（R20.96）.Moreover,the research results of thermodynamic sorption experiments demonstrate that the sorption of NB onto the K-Mt is a spontaneous exothermic process mainly controlled by both the hydrophobic bonding and n-π electron-donor-acceptor（EDA） interaction between clay mineral surface and nitrobenzene.The presence of K＋ ion is likely to be a favorable factor due to increasing some sorption sites and improving the accessing condition for sorption,leading to the promotion of sorption for NB onto the K-Mt.