腐植酸对土壤重金属镉的淋溶效果及吸附解吸机制研究

摘要

In order to investigate the remediation of humic acid on heavy metal cadmium (Cd) in soil, simulation ex-periment of soil column leaching and adsorption-desorption method were used in terms of different dosages of humic acid and the effects on adsorption-desorption were demonstrated under different soil pH value. The results showed that different dosage of humic acid could lead different amount of Cd in leaching solution and the amount of Cd did not decrease with increasing of the dosage of humic acid. However, when the dosage of humic acid reached certain con-centration, Cd in the solution reduced to the stable trend. Under acid conditions, the humic acid adsorption quantities of experimental treatments were signiifcant. Under alkaline conditions, when pH=11, the soil adsorption quantities of ex-perimental treatments were all high, and had no obvious difference. According to the results of desorption, as increasing of pH, the soil desorption quantities of Cd decreased, and under condition of pH=11, the soil desorption quantities were lowest, and there were no signiifcant difference among all treatments.%为了揭示腐植酸对土壤重金属镉(Cd)的淋溶效果及吸附解吸机制，本研究采用土柱模拟淋溶方法和吸附解吸试验方法，开展不同腐植酸用量对土壤重金属Cd的淋溶试验，以及pH变化对土壤Cd吸附解吸效应。结果表明，不同腐植酸用量导致土壤淋溶液中Cd含量有别，淋溶液中Cd含量并不随土壤腐植酸用量的增加而减少，而是当腐植酸的用量达到一定浓度时，淋溶液中Cd含量减少趋稳。在酸性条件下，各处理腐植酸对Cd的吸附性显著；在碱性条件下，当pH=11时，各处理土壤对Cd的吸附量达到最大且基本稳定。解吸试验显示，随着pH增加，各处理的解吸量不断减小，当pH=11时，各处理土壤对Cd的解吸量最小，处理间差异不显著。