高岭土中铅污染物的电动迁移及去除  

Electrokinetic migration and removal of lead pollutants in kaolin

作　　者：刘志涛 庄艳峰[1] LIU Zhi-tao;ZHUANG Yan-feng(School of Civil Engineering,Wuhan University,Wuhan 430072,China)

机构地区：[1]武汉大学土木建筑工程学院,湖北武汉430072

出　　处：《岩土工程学报》2020年第7期1359-1367,共9页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(41472039,51109168)。

摘　　要：以人工配制的铅污染高岭土为研究对象,引入新型电动土工合成材料电极,研究铅污染土的电动修复机理。采用两种不同的电动修复手段,通过分析电动修复过程中的电流、土体pH以及铅元素的存在形态,研究不同添加剂对铅污染土去除效率的影响及两种修复手段的差异性。结果表明:电动修复换水试验电流后期存在明显下降阶段,而循环试验电流后期没有下降,而是小幅波动;针对铅污染物修复而言,醋酸类添加剂比柠檬酸类添加剂更有利于铅的去除;柠檬酸与铅离子易生成难电离物质不利于铅的迁移,乙二胺四乙酸二钠能与绝大多数铅离子络合形成络合离子;通过蠕动泵循环阴、阳极电解液可以较好地控制电解水产生的氢离子和氢氧根,避免其对土体pH及重金属形态产生明显影响;修复试验中离子扩散和电解液循环引起的冲刷作用迁移出的重金属较少,占比小于10%,进一步说明电动法去除土体重金属污染物的有效性。The artificially prepared lead-contaminated kaolin is used as the research object with a new type of electrokinetic geosynthetics(EKG) as electrode to study the mechanism of electrokinetic remediation of lead-contaminated kaolin. Two different electrokinetic remediation methods are used. The effects of different additives on the removal efficiency of heavy metals in contaminated soil and the differences of the two repair methods are studied by analyzing the current, soil pH and the existing forms of lead elements. The results show that the later stage of current variation for the renewal electrolyte method of electrokinetic remediation tests has a significant decline pattern, while that for the electrolyte cycle method has a slightly fluctuating pattern instead. For the remediation of lead-contaminated soil, the additive of the acetic is more effective to the removal of lead than that of the citric. Citric acid and lead ions are easy to form substances that are difficult to ionize, which is poor for lead migration. The ethylenediaminetetraacetic acid disodium can complex with most lead ions to form complex ions. The hydrogen ion and hydroxide radical produced by electrolytic water can be well controlled by circulating cathode and anode electrolyte with peristaltic pump, so as to reduce their impact on the soil pH and heavy metal speciation. In the tests, the removal of heavy metals by ion diffusion and scouring caused by the electrolyte circulation is less than 10%. This further illustrates the effectiveness of the electrokinetic method in removing heavy metal contaminants from soil.

关 键 词：电动修复 铅污染高岭土 添加剂 循环电解液 电动土工合成材料(EKG) 

分 类 号：TU443[建筑科学—岩土工程]