膨润土负载壳聚糖修复土壤镉污染的效果  

Adsorption effect of cadmium (Ⅱ) in soil with chitosan loading on bentonite

作　　者：李增新[1] 王彤[1] 张道来[2] 刘哲[1] 

机构地区：[1]青岛大学师范学院化学系,山东青岛266071 [2]国家海洋局第一海洋研究所,山东青岛266071

出　　处：《生态环境》2008年第1期241-244,共4页Ecology and Environmnet

基　　金：青岛市科技发展计划项目(05-1-NS-58)

摘　　要：随着重金属污染土壤日益加剧,污染土壤修复和控制技术的研究越来越迫切。为利用膨润土原位修复土壤镉污染提供理论依据,采用平衡吸附试验研究了Cd2+在膨润土负载壳聚糖上的吸附行为。以90%脱乙酰度壳聚糖为原料,制备了膨润土负载壳聚糖颗粒吸附剂,用于吸附溶液中Cd2+。试验探讨了壳聚糖质量浓度对负载率的影响,结果表明,质量浓度3%的壳聚糖负载量最大,壳聚糖最大负载率达32.6%。吸附Cd2+最佳工艺条件是:壳聚糖与膨润土质量比为1∶20,膨润土负载壳聚糖颗粒吸附剂用量为15g·L-1,溶液中Cd2+含量不大于200mg·L-1,pH值为6～8,吸附平衡时间为8min,Cd2+去除率为99%。动态吸附Cd2+试验结果表明:质量浓度为200mg·L-1的含Cd2+溶液,流速为4～6m·h-1,经壳聚糖-膨润土吸附剂一次处理后,溶液中Cd2+的残留量为0.7mg·L-1。With the heavy metal contaminated soil increasing, the requirement of remediation and control technology becomes urgent. Although nonmetallic mines have been used widely as soil amender, there are few reports for remedy heavy metal contaminated soil especially for cadmium （Ⅱ） contaminated soil. For the purpose of providing a new way to control and remedy cadmium （Ⅱ） contaminated soil, the equilibrium adsorption isotherm experiments were conducted to investigate the effect of the adsorption behaviors toward Cd^2＋ in solution on bentonite -chitosan. The effect of chitosan loading rate on bentonite was test from different chitosan concentration by determining the coating rate of chitosan on bentonit.The results indicates that the maximum of chitosan loading rate on bentonite was 32.6% as the mass concentration of chitosan 3%.The optimum technology condition of adsorption cadmium （Ⅱ） in solution with chitosan loading on bentonite was obtained as follows： bentonite was added in chitosan slurry of 90% the degree of deacetylation to prepare adsorbent which mass ratio is 1：20, the dosage of the adsorbent is 15 g·L^-1, the mass concentration of Cd（ II ） in solution does not exceed 200 mg·L^-1, the pH value 6-8, the adsorption equilibrium time is about 8 min and Cd（Ⅱ） removal efficiency is 99%.The dynamic experiment results show that when Cd2＋mass concentration 200 mg·L^-1, fluid speech 4 - 6 m·h^-1, after through adsorbent remainder of Cd^2＋in solution 0.7 mg·L^-1.

关 键 词：土壤污染治理 膨润土 壳聚糖 吸附剂 镉离子 

分 类 号：X53[环境科学与工程—环境工程]