壳聚糖负载MnO_2对As(Ⅲ)的吸附性能研究  

Study on the adsorption behavior of As(Ⅲ)by MnO_2loaded chitosan

作　　者：李爱阳[1] 蔡玲[1] 贺惠[1] 

机构地区：[1]湖南工学院化工系,湖南衡阳421002

出　　处：《安全与环境学报》2011年第4期61-64,共4页Journal of Safety and Environment

基　　金：湖南省自然科学基金项目(08JJ3015);湖南省教育厅科研计划项目(07C030);衡阳市工业科研开发计划项目(06KG59)

摘　　要：利用壳聚糖负载MnO_2制备一种复合吸附剂。研究了溶液pH值、吸附时间、温度对As(Ⅲ)吸附行为的影响,并探讨了吸附动力学。结果表明,在pH值为5～8,吸附时间为60 min,温度为60℃,复合吸附剂对As(Ⅲ)的吸附率达98%以上,吸附能力明显优于壳聚糖。对试验数据运用相关数学模型拟合表明,复合吸附剂对As(Ⅲ)的吸附符合Langmuir和Freundlich吸附等温式,最大吸附量q_(max)为19.798mg/g,特性常数n为4.334 1,决定系数R^2分别为0.997 5、0.980 4。吸附过程动力学适合二级动力学方程。The paper was aimed to explore a relatively cheap and practical composite material for metal ion removal from wastewater. An efficient composite adsorbent was prepared by loading chitosan with MnO2. The experimental results showed that when the deacetyla- tion degree of ehitosan was 90% and when the ratio of ehitosan and MnO2 as 1：0.06, the composite adsorbent exhibited optimum performance of adsorption. The discussion is focused on the adsorption ca- pacity of the composite adsorbent on As （ 1H ）, and a comparison of adsorption efiqciency between the composite adsorbent and chitosan is also reported. Generally, it can be said that the composite adsorbent exhibited higher adsorption capacity than chitosan due to higher numbers of active binding sites. Factors such as ptt value, adsorption time and temperature that affecting the As （Ⅲ） adsorption efficiency were examined. The concentration of As（Ⅲ） in the solution after ab- sorption was tested by atomic absorption speetrophotometer. The result showed that when pH value 5 8, adsorption time 60 min and temperature 60 ~C, the adsorption capacity for As（ 111 ） was able to reach 98% and the adsorbent efficiency was better than chitosan. The maximum capacity was increased by 67.34%, from ll.871 mg/g to 19.798 mg/g As（ Ⅲ ）. The treated effluent has met the first-class standard of National Wastewater Discharge Standard（ GB 8978-- 1996）. By fitting the experimental data with related mathematic models, it showed that the adsorption equilibrium isotherm complied with Langmuir and Freundlieh models. The maximum adsorption quantity qmx was 19.798 mg/g and the characteristic constant n was 4. 334 1, respectively. The adsorption kinetic was found to obey second-order reaction. The adsorption of As （Ⅲ） by MnO2 loaded chitosan is a complicated process. Chemical adsorption and physical ad- sorption were suggested to be the main adsorption mechanism through- out the process.

关 键 词：环境工程学 吸附 壳聚糖 吸附等温 性能 动力学 

分 类 号：X703[环境科学与工程—环境工程]