Effect of Citric Acid on immobilization of Heavy Metals

4th International Conference on Energy Equipment Science and Engineering

Liu, Gaojie^1

Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, China^1

关键词: Acid concentrations;    Chemical immobilization;    Ecological environments;    Environmental conditions;    Heavy metal contaminated soils;    Heavy metal pollution;    Heavy metals in soil;    International standards;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/242/5/052020/pdf
DOI  :  10.1088/1755-1315/242/5/052020

来源: IOP

【 摘 要 】

Heavy metal pollution of soils has become increasingly serious, and chemical immobilization is usually used to remediate heavy metal contaminated soil. With changing environmental conditions, the immobilization heavy metal may be released again, which is a risk to ecological environment and human health. In the study, sepiolite is applied to the heavy metal contaminated soil (0.5%, 2%, 5%), training for 60 days, adding 2mmol/Kg, 10mmol/Kg and 20mmol/Kg citric acid into the contaminated soil. This research adopted characteristic leaching procedure (TCLP) to evaluate the remedition effect and BCR to analysis the change of heavy metal species of soil. The results show that, no adding citric acid, the content of TCLP-Cd decreased with the increase of sepiolite addition ratio. When the sepiolite addition ratio was 5%, TCLP-Cd is lower than its of TCLP international standards. It shows that sepiolite can effectively remediate heavy metals in soil. When the proportion of sepiolite is constant, low concentration of citric acid is helpful to remedition, while high concentration of citric acid is not conducive to remediation of heavy metals. BCR method showed that the exchangeable content increased with the increase of citric acid concentration, but the oxidizable content decreased, indicating that citric acid could increase the bioavailability of heavy metals.