柠檬酸与皂素对重金属污染土壤的联合淋洗作用  

Combined Leaching of Heavy Metals in Soil by Citric Acid and Saponin

作　　者：许中坚[1] 许丹丹[1] 郭素华[1] 邱喜阳[1] 李方文[1] 

机构地区：[1]湖南科技大学化学化工学院,湖南湘潭411201

出　　处：《农业环境科学学报》2014年第8期1519-1525,共7页Journal of Agro-Environment Science

基　　金：国家自然科学基金(20577008);湖南省自然科学基金(05JJ30017)

摘　　要：以重金属Zn、Pb、Cu复合污染土壤为对象,采用淋洗方法,研究了柠檬酸与皂素对人工污染土壤的联合淋洗修复效果。结果表明,40 mmol·L-1的柠檬酸与质量分数为3%的皂素在体积比为1∶5的情况下对重金属Zn、Pb淋洗的累计去除效率较高,分别为67.2%,68.8%;在体积比为1∶1时对Cu的累积去除率较高,为37.7%,不及单独用柠檬酸淋洗的效果好。柠檬酸与皂素对土壤中重金属淋洗的联合效应与二者的体积比和重金属种类有关,两者的联合淋洗可去除Zn的96%酸溶态、38.9%可氧化态,淋洗后可还原态显著增加;Pb酸溶态、可还原态均减少了80%左右;Cu的酸溶态、可还原态减少了80%以上,可氧化态和残渣态则没有显著性变化。Soil contamination with heavy metals has become an increasingly severe global environmental issue. Considerable efforts have been made to remediate contaminated soils. In this study, Zn, Pb and Cu spiked soil was employed to evaluate leaching of metals from the soil with citric acid and saponin. First, optimal concentration of citric acid or saponin was determined in mono-leaching experiments with single citric acid or saponin. Second, removal rates of heavy metals were examined by co-leaching of citric acid and saponin at their optimal concentrations. Finally, chemical species of heavy metals in soils after co-leaching were analyzed using BCR procedure. The optimal concentration of citric acid was 40 mmol·L^-1and saponin 3%. The removal rates of Zn and Pb were greatest at 1∶5 volume ratio of citric acid to saponin solution, being 67.2% and 68.8%, respectively. However, the greatest removal rate of Cu was 37.7%, at 1 ∶1 volume ratio of citric acid to saponin, less than that of citric acid alone. Compared to the control, combined leaching removed 96% of acid soluble, 38.9% of oxidizable and 51.5% of residual Zn, but increased reducible Zn significantly. Leaching reduced both acid soluble and reducible Pb and Cu by80%. Oxidizable and residue Cu did not change significantly after leaching.

关 键 词：重金属 污染土壤 柠檬酸 皂素 联合作用 淋洗 

分 类 号：X171.5[环境科学与工程—环境科学]