低分子有机酸对土壤中重金属的解吸及影响因素

研究了柠檬酸、草酸、酒石酸和苹果酸对矿区土壤中重金属Pb、Cd、Cu和Zn的解吸行为,并探讨了介质pH值对其解吸土中重金属的影响。振荡解吸试验结果表明四种低分子有机酸对供试污染土壤中Pb、Cd、Cu和Zn都具有一定的解吸能力。由于土壤中重金属有效态含量较低,各重金属的解吸率都不高。在对Pb和Cd的解吸中,各低分子有机酸能力大小顺序为柠檬酸>酒石酸≈苹果酸>草酸;Cu的解吸顺序为柠檬酸>草酸>酒石酸≈苹果酸;Zn的解吸顺序为酒石酸>柠檬酸≈苹果酸>草酸。低分子有机酸随浓度的增加,其解吸能力提高。低分子有机酸对重金属的解吸量随pH值的降低而增加。

Effect of Low Molecular Weight Organic Acids on Desorptions of Pb, Cd,Cu and Zn from soils

Effects of low molecular weight organic acids (LMWOAs) on Pb,Cd,Cu and Zn from contaminated soils were studied.The results showed that Pb,Cd,Cu and Zn in the soil were partly dissolved by four LMWOA solutions under different concentrations in batch experiment.The desorption sequence of each LMWOA for different heavy metals were in the order of citric>tratric≈succinic>oxalic (for Pb and Cd), citric>oxalic>tratric≈succinic (for Cu), tratric>citric≈succinic>oxalic (for Zn).The concentrations of heavy metals in solution were enhanced with the increasing of LMWOAs density and the decreasing of pH.