福建某铬污染地块土壤淋洗剂筛选及条件优化研究

Selection and Condition Optimization of Soil Chemical Leaching Agent for Chromium Contaminated Sites in Fujian Province

本文以福建某重金属污染地块中铬污染土壤为供试土壤,在实验室考察了4种淋洗剂草酸、硫酸亚铁、硫代硫酸钠和柠檬酸对总铬和六价铬(Cr(VI))的淋洗去除效果,筛选出了最佳淋洗剂,并通过实验确定了最佳淋洗条件,包括淋洗剂浓度、液固比以及淋洗时间。实验结果表明,草酸对总铬和Cr(VI)的淋洗去除效果最好,其最佳淋洗条件为:浓度为0.1 mol/L,液固比为4 mL/g,淋洗时间为1 h。在此条件下,土壤中总铬和Cr(VI)的去除率分别为69.58%和91.42%,该工艺参数可作为现场施工的依据。

In this paper,the chromium-contaminated soil in a heavy metal-contaminated site in Fujian was selected as the test soil,the removal rate of four leaching agents such as oxalic acid,ferrous sulfate,sodium thiosulfate and citric acid on total chromium and hexavalent chromium(Cr(VI))were investigated in the laboratory,the best leaching agent was screened out,and the process parameters such as the dosage of leaching agent,liquid-solid-ratio,and reaction time were determined.The experimental results show that oxalic acid has the best removal rate on total chromium and Cr(VI),and the optimum leaching conditions were as follows:the concentration is 0.1 mol/L,the liquid-solid ratio is 4 mL/g,and the leaching time is 1 h,which can be used as the basis for soil washing.Under this condition,the removal rate of total chromium and Cr(VI)were 69.58%and 91.42%,respectively.