络合剂淋洗Cu污染粉土的土柱试验研究

A study of soil column experiments for copper contaminated silt flushed by chelating agents

以当前我国备受关注的土体污染为背景,通过土柱试验研究了不同络合剂对Cu的淋洗效果,结果表明:乙二胺四乙酸二钠二水合物(ethylenediaminetetraacetic acid disodium saltdihydrate,EDTA)淋洗效果最佳,柠檬酸(citric acid,CIT)次之,氨三乙酸三钠盐单水合物(nitrilotriacetic acid trisodium salt monohydrate,NTA)淋洗效果相对最差;使用不同浓度的EDTA淋洗负载量为150 mg/kg的Cu污染土,浓度增大并未有效促进Cu的解吸,而较小浓度(0.005 mol/L)的EDTA是有效且经济的浓度,其对Cu的去除率达84%;0.015 mol/L的EDTA淋洗不同负载量的Cu污染土,随负载量增加,淋洗率下降,最高去除率为84%,但去除量增加;研究结果可为重金属污染土的淋洗修复工艺提供理论参考依据。

Great attention has been paid to soil contamination in China. Therefore,a series of soil column experiments were conducted to examine the removal behavior of copper from silty soil flushed with different chelating agents. The results indicate that the removal efficiency of copper was different when using different chelating agents the efficiency is in the order of EDTA CIT NTA. The increasing EDTA concentration was not effective in promoting copper removal. 0. 005 mol/L of EDTA is an effective and economic concentration and the removal ratio can reach 84%. When the concentration of EDTA is 0. 015 mol/L,the removal ratio of copper decreases with the increasing concentration of copper in silt,and the largest removal ratio is 84%,while the removal amount of cooper increases. The results can provide theoretical reference for the heavy metal contaminated soil remediation process.