土壤环境中重金属元素的相互作用及其对吸持特性的影响

本文用正交试验法研究了Cd,Pb,Cu,Zn、As五种元素复合作用时土壤颗粒的吸附解吸特性.结果表明:供试元素的吸附过程均符合Langmiur方程,其吸持能力依次为Pb>As>Cu>Zn>Cd,而最大吸附量顺序正好相反.Cd,As为复合污染的主要因子,同时还显著地影响其它元素的吸附解吸过程.土壤对重金属元素的吸附和解吸量不仅与平衡溶液中元素浓度有关,而且还明显地受共存元素及其交互作用的影响,交互作用的结果与元素间的相对浓度及其比例有关.AsO_4~(3-)的存在使Cd,Pb,Cu,Zn的吸附解吸过程变得极为复杂,这可能与产生重金属盐沉淀和次级吸附和解吸有关.

EFFECTS OF HEAVY METALS JOINT ACTION ON THEIR CHARACTERISTIC OF SORPTION AND DESORPTION IN BROWN SOIL

The effects of heavy metals joint action on the characteristic of the elements sorp-tion and desorption in soil was studied with orthogonal experimental method. The results show that the sorptions of the tested elements obey the Langmiur equation C/ (X/ m ) =1/Kb+C/b. The order of the sorption potentials of the elements on soil is Pb>As X3u>Zn>Cd, but that of the sorption maximum is reverse. Cd, Pb,Cu,Zn, As, which depend not only on their toxicity, but also on their activity and desorptivity, further they effect strongely the sorption and desorption of other elements. The amounts of elements sorption and desorption are relative to the coexistant elements and their interaction besides the concentrations of elements in the equilibrium, and the results of the interaction depend on their relative contents and ratios of coexistant elements. The sorption and desorption become more complicated in the pressence of AsO43- the mechanism may be the sediment of heavy metal salt and the secondary sorption and desorption.