摘要
选取三氯化铁和有机酸(柠檬酸、苹果酸、酒石酸)复合淋洗,采用土柱淋洗的方法对Cd、Pb污染土壤进行淋洗实验,研究了复合淋洗剂浓度配比、淋洗剂用量和淋洗次数对重金属去除效果的影响,并测定了土壤淋洗前后Cd、Pb形态的变化。结果表明:三氯化铁浓度为10 mmol/L,有机酸浓度为20 mmol/L时,淋洗率Cd为72.15%,Pb为30.26%,与使用单一淋洗剂相比均有大幅提升。复合淋洗剂能有效地去除交换态、碳酸盐结合态和氧化物结合态重金属,而对有机态和残余态部分重金属作用效果不明显;Cd比Pb容易去除是由于污染土壤中Cd的存在形态主要是可交换态、碳酸盐结合态和铁锰氧化物结合态,而Pb的存在形态主要是有机结合态和残渣态。淋洗后土壤中Cd和Pb均达到土壤环境质量标准。
Simulated soil column leaching experiment in laboratory using Fe Cl3 and organic acid( citric acid,malic acid,tartaric acid) were conducted to study the composite leaching agent concentration,dosage and the leaching times. And the chemical forms of Cd and Pb in the contaminated soil were determined before and after column leaching. The results showed,the optimum concentrations were 10 mmol / L( Fe Cl3) and 20 mmol/L( organic acid). And the removal rates of Cd and Pb were 72. 15% and 30. 26%,respectively. The efficency of composite leaching agent had increased substantially compared with using a single leaching agent. Composite leaching agent could effectively remove exchange status,carbonate status and oxide combination patterns of heavy metals,and the effect on organis status and residual status was not obvious. The removal of Cd was easier than Pb,which mainly due to the presence of Cd in contaminated soil was exchange status,carbonate status and iron manganese oxide status,while the existence of Pb was mainly the organic status and residual status. After leaching,Cd and Pb in the soil achieved the environmental quality standards.
出处
《环境工程》
CAS
CSCD
北大核心
2015年第1期163-167,共5页
Environmental Engineering
基金
江苏省科技支撑项目(BE2013711)
中央高校基本科研业务费专项资金资助(KYZ201323)
关键词
土壤污染
土柱淋洗
重金属
复合淋洗
soil pollution
column leaching
heavy metals
composite leaching
