汞矿区汞污染土壤的淋洗修复

摘要

以贵州省铜仁市汞矿区汞污染土壤为研究对象,分别采用KI、Na2S2O3、乙二胺四乙酸、柠檬酸、酒石酸、十二烷基硫酸钠溶液对其进行淋洗修复,筛选出合适的淋洗剂,优化了淋洗条件,并探索了淋洗液的处理方法.实验结果表明:对该土壤淋洗效果最好的淋洗剂为Na2S2O3,最佳淋洗条件为Na2S2O3浓度0.01 mol/L、固液比(g/mL)1:5、淋洗时间4 h、淋洗次数1次,在此条件下土壤中总汞的淋洗率为13.41%,有效态汞含量可降至原来的61.54%;Na2S对淋洗液中的汞具有较好的去除效果,每升淋洗液加入0.6 g Na2S处理后,即可满足GB 8978-1996《污水综合排放标准》.%The mercury contaminated soil from mercury mining area in Tongren,Guizhou,China was remediated by washing with KI,Na2S2O3,ethylene diamine tetraacetic acid,citric acid,tartaric acid,sodium dodecyl sulfate solution,respectively. The appropriate washing agent was screened,the washing conditions were optimized and the method for leacheate treatment was studied. The experimental results showed that:The washing agent with best effect on the mercury contaminated soil was Na2S2O3;Under the optimum washing conditions of Na2S2O3concentration 0.01 mol/L,solid-to-liquid ratio (g/mL)1:5,washing time 4 h and washing frequency 1,the washing rate of total Hg in soil was 13.41% and the concent of bioavailable Hg was decreased to 61.54% of the original;Na2S was effective for removal of Hg from the leachate,and the Hg content in leachate met the national wastewater discharge standard GB 8978-1996 after treatment with Na2S addition of 0.6 g per liter.