阳离子表面活性剂用量对改性沸石吸附铬酸根的影响  

Effects of Surfactant Modifying Zeolite on Adsorption of Chromate.

作　　者：吴建军[1] 徐仁扣[2] 肖双成[2] 姜军[2] 

机构地区：[1]南京农业大学资源与环境学院,江苏南京210095 [2]中国科学院南京土壤研究所/土壤与农业可持续发展国家重点实验室,江苏南京210008

出　　处：《生态与农村环境学报》2007年第3期82-85,共4页Journal of Ecology and Rural Environment

基　　金：国家"十一五"科技支撑计划项目(2006BAJ10B06)

摘　　要：用不同量阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)对天然沸石改性,并制备不同改性程度的改性沸石,测定沸石对CTAB的吸附量,比较几种沸石对铬酸根的吸附性能及其与改性沸石胶体Zeta电位的关系,探讨沸石对铬酸根的吸附机制及沸石再生后对铬酸根的吸附能力。结果表明,随着CTAB加入量的增加,它在沸石表面的吸附量显著增加,制备的改性沸石对铬酸根吸附性能显著提高。改性后沸石胶体的Zeta电位由负变正,而且随着CTAB用量的增加,Zeta电位正值增加。铬酸根在改性沸石表面的吸附量随离子强度增加而减小,而且改性沸石吸附的铬酸根大部分可以被中性盐解吸,说明铬酸根的吸附以静电作用机制为主。改性剂用量在0.15～0.3 mol.kg-1范围内,改性沸石再生后仍对铬酸根有很好的吸附性能,可以循环使用。Zeolite was modified to a varying extent with cation surfactant CTAB （hexadecyhrimethylammonium bromide） added at different rates and amount of CTAB adsorbed by different modified zeolites was determined. Then comparison was made between these modified zeolites in chromate adsorption capacity and in relationship between chromate adsorption on modified zeolites and Zeta potential in its suspension system, to explore mechanism of chromate adsorption by zeolite, and adsorption capacity of renewed zeolites. Results show that with the rising CTAB application rate, beth CTAB adsorption on zeolite and chromate adsorption capacity of the modified zeolite increased obviously. And so did the Zeta potential of zeolite, turning from negative into positive after modification by cation surfactant. It is hence clearly indicated that the adsorption of cation surfactant on zeolite induced a change in its surface charge properties. Chromate absorption by the modified zeolites decreased with the increase in ionic strength, and most of the chromate adsorbed on modified zeolites can be desorbed by neutral salt, which suggested that the electrostatic interaction between the modified zeolite and chromate was the major mechanism for the enhanced adsorption of chromate. If addition of CTAB is controlled in the range from 0. 15 to 0. 30 mol·kg^-1, the used modified zeolite can be renewed for use again as absorbent for chromate.

关 键 词：十六烷基三甲基溴化铵(CTAB) 改性沸石 铬酸根 吸附-解吸 

分 类 号：X131.3[环境科学与工程—环境科学]