有机膨润土对敌敌畏的吸附性能研究  

Studies on the Sorption of DDVP on Cetyltrimethylammonium Bromide Bentonite

作　　者：余晓皎[1] 孟瑞军[1] 张健[1] 张建丰[1] 刘广钧[1] 

机构地区：[1]西安理工大学理学院,西安710054

出　　处：《环境科学》2011年第6期1745-1750,共6页Environmental Science

基　　金：国家自然科学基金项目(50779055)

摘　　要：采用批量平衡实验,研究了阳离子表面活性剂十六烷基三甲基溴化铵(CTMAB)改性的有机膨润土及原土对有机磷农药DDVP的吸附性能,并考察了pH、温度以及CaCl2浓度对吸附的影响.结果表明,改性膨润土对水中DDVP的去除能力优于原土,并且吸附量随着改性剂量的增加而增大,即1.0CEC>0.6CEC>0.3CEC>0.0CEC.有机膨润土及原土在低浓度范围内对DDVP的吸附可以用Henry和Freundlich等温模型很好的拟合(R2>0.98),表明吸附为线性分配.碱性条件下由于DDVP水解,静电引力和分配作用共同作用使得有机膨润土对DDVP的吸附量较酸性条件有显著的提高;温度由25℃变化到45℃,吸附的自由能变和焓变均为负值,表明吸附为自发的放热反应;CaCl2的浓度由0.1 mol/L变化到2.0 mol/L时,1.0CEC有机膨润土对DDVP的吸附分配系数Kd约增加了10倍,CaCl2的加入不仅提高了有机膨润土的稳定性,而且使体系存在盐效应.The sorption of organophosphorus pesticide dichlorvos（DDVP） by natural and cetyltrim-ethylammonium bromide（CTMAB） modified bentonite was investigated using a batch equilibrium technique,and the effect of pH,temperature and CaCl2 concentration were also observed.The results show that the sorption capacity of those modified bentonites to remove DDVP from aqueous solution seems to be more effective than unmodified sample,and the capacity of organobentonite is enhanced with the increased modifier loading,1.0CEC 0.6CEC 0.3CEC 0.0CEC.The sorption patterns date of DDVP onto original and organic bentonite are correlated well by Henry and Freundlich isotherm models,suggesting that sorption can be described by a distribution process.Because of dissociation under alkaline solution,the sorption of DDVP onto organobentonite is found to be better than that of acid solution,which has mainly resulted from electrostatic force and distribution process.The sorption of DDVP onto CTMAB-bentonite is definitely exothermic in nature due to the negative ΔH0 and ΔG0 values in the temperature range of 25-45℃.The Kd of DDVP increased nearly by 10 times for 1.0CEC organobentonite when concentration of CaCl2 was in the range of 0.1-2.0 mol/L,which mainly result from stability and salt effect.

关 键 词：有机膨润土 敌敌畏 吸附性能 影响因素 农药污染 

分 类 号：X131.2[环境科学与工程—环境科学]