低分子量有机酸对江西省典型水稻土中铅离子吸附解吸的影响

Effects of Low Molecular Weight Organic Acids on Adsorption and Desorption of Pb(Ⅱ) in the Typical Paddy Soil in Jiangxi Province

【目的】通过研究有机酸对水稻土中铅离子吸附解吸的影响,为铅在水稻土中的环境化学行为和重金属污染修复提供科学依据和指导,对治理江西省水稻土的铅污染具有现实意义。【方法】以江西省潜育型和潴育型2种典型水稻土为试材,采用振荡平衡法研究不同种类的低分子量有机酸对水稻土中铅离子吸附解吸的影响。【结果】在相同pH条件下,柠檬酸抑制了对铅离子的吸附,丙二酸、苹果酸和酒石酸均不同程度的促进了2种水稻土对铅离子的吸附,且潴育型的吸附量大于潜育型;而柠檬酸促进了对铅离子的解吸,丙二酸、苹果酸和酒石酸均不同程度的抑制了2种水稻土对铅离子的解吸,且潴育型的解吸率小于潜育型;在不同pH条件下,2种水稻土对铅离子的吸附量均随pH升高而增大;而2种水稻土对铅离子的解吸率均随pH升高而减小。【结论】加入柠檬酸有利于减少水稻土对铅的吸附,而丙二酸、苹果酸和酒石酸均增加了铅对水稻土的污染风险。

[Objective]The study of the effect of organic acids on the adsorption and desorption of lead ions by paddy soil,will provide scientific basis and guidance for the environmental chemical behavior of lead in paddy soil and the remediation of heavy metal pollution,it is important to the control of lead pollution of rice soil in jiangxi province[.Method]Two kinds of typical Waterlogged paddy soil(WPS)and gley type paddy soil(GTPS)in Jiangxi Province were chosen as the test materials,the effects of different kinds of low molecular weight organic acids(LMWOA)on the characteristics of Pb2+adsorption and desorption of paddy soil were studied with anoscillatory equilibrium method.[Result]Under the same pH condition,citric acid inhibited the adsorption of Pb(Ⅱ),and that malonic acid,malic acid and tartaric acid promoted the adsorption of lead ions by the paddy soils to varying degrees,and the adsorption capacity of WPS was greater than that of GTPS,and citric acid promoted the desorption of Pb(Ⅱ),and that malonic acid,malic acid and tartaric acid inhibited the desorption of lead ions by the paddy soils to different degrees,and the desorption rate of GTPS was greater than that of WPS.Under different pH conditions,the adsorption capacity of lead ions of the two paddy soils increased with the increase of pH value,and the desorption rate of lead ions of both the paddy soils decreased with the increase of pH value[.Conclusion]The addition of citric acid can reduce the absorption of lead by paddy soils,and that malonic acid,malic acid and tartaric acid increase the risk of lead contamination to paddy soil.