柠檬酸淋洗修复黏性土壤重金属污染研究

Study on the Repair of Heavy Metal Pollution in Clay by Citric Acid Leaching

摘要: 土壤重金属污染日益严重，淋洗修复技术成为研究的热点。以柠檬酸淋洗黏性土壤重金属污染物，采用震荡淋洗法研究淋洗剂浓度、固液比、淋洗时间对Cu、Zn、Ni、Pb、As去除效果的影响，分析淋洗前后土壤基本理化性质的变化。结果表明：柠檬酸对黏性土壤重金属具有一定的淋洗效果，对复合重金属的去除能力依次为Cu > Zn > Ni > Pb > As；Cu和Ni受淋洗剂浓度影响较大；固液比通过影响黏土颗粒分散而影响淋洗效果；柠檬酸对重金属的快速反应阶段均在40 min内，在180 min达到淋洗平衡；柠檬酸淋洗后的黏性土壤孔隙率、有机质含量升高有利于土壤再利用过程中微生物的生长及繁衍。

Abstract: Soil heavy metal pollution is becoming more and more serious and leaching repair technology has become a hot topic. Heavy metal pollutants in clay were washed with citric acid. The effects of leaching agent concentration, solid-liquid ratio and leaching time on the removal efficiency of Cu, Zn, Ni, Pb and As were studied by shock leaching. The results showed that citric acid had a certain leaching effect on heavy metals in clay, and the removal capacity of complex heavy metals was Cu > Zn > Ni > Pb >As. Cu and Ni were greatly affected by the concentration of leaching agent. The solid-liquid ratio affects the leaching effect by affecting the dispersion of clay particles. The rapid reaction stage of citric acid to heavy metals was all within 40 min and the elution equilibrium was reached at 180 min. The increase of porosity and organic matter content after citric acid leaching was beneficial to the growth and reproduction of microorganisms in the process of soil reuse.