动电技术去除城市污泥中镉的研究  

Removing cadmium from sewage sludge by electrokinetic remediation technique

作　　者：陈铭[1] 李小明[1] 杨麒[1] 曾光明[1] 张莹[1] 胡劲梅[1] 廖青[1] 

机构地区：[1]湖南大学环境科学与工程学院,长沙410082

出　　处：《环境工程学报》2008年第8期1110-1114,共5页Chinese Journal of Environmental Engineering

基　　金：国际科技合作重点项目(2004DFA06200);新世纪优秀人才支持计划(NCET-04-0770)

摘　　要：采用实际城市污泥为研究对象,通过控制阴极液酸度和添加络合剂,考察了镉的动电过程.结果表明,添加EDTA和柠檬酸不仅改变了动电过程的电流和电渗流,同时对镉的形态分布也产生了明显的影响：存在于移动性较低形态、难以去除的镉被转化为移动性较高的形态,在动电作用下从污泥中移除,从而提高了动电处理的效率,总镉的去除率最高达到70.1%;EDTA和柠檬酸对动电处理的促进作用主要受体系酸度的影响,其中控制阴极pH值为4和8时,总镉的去除率达到66.%、70.1%、62.3%和66.5%,较pH值为6时去除率提高了2～3倍。比较两种络合剂,EDTA在高pH值条件下对镉的络合能力较强而表现出较高的去除率,而柠檬酸对酸度的适应性相对较强。The effects of controlling acidity of cathode pond solution and adding complex agents on Cd electrokinetic processes in actual sewage sludge were investigated. The results showed that adding EDTA and citric acid not only changed the quantity of current and electroosmotic flow, but also affected the speciation of Cd significantly. The fraction of Cd which was immobile and strongly bound was transformed to mobile and weakly bound fraction, and was moved out of sewage sludge by electrokinetic action. Therefore, the removal efficiency of electrokinetic processes was improved and the maximum reached 70.1%. The promoting effect of EDTA and citric acid to electrokinetic processes mainly depended on the acidity of system, in which the removal rates were 66.4%, 7.1%, 62.3% and 66.5%, respectively at pH 4 and 8, near 2～3 times higher than those at pH 6. Compared with citric acid, EDTA was more efficient under high pH condition, due to the stronger ability of complexation, and citric acid had a wider pH range of applying.

关 键 词：城市污泥 镉 动电过程 形态分布 络合剂 

分 类 号：X705[环境科学与工程—环境工程]