环境材料对污染土壤中Pb、Cd和As的吸附解吸研究

ADSORPTION AND DESORPTION OF ENVIRONMENTAL MATERIALS ON Pb,Cd AND As IN CONTAMINATED SOIL

通过模拟实验考察了环境材料沸石(FS)和蛇纹石(SS)在不同pH值下对土壤Pb、Cd、As的吸附与解吸结果,探索环境材料对土壤重金属的固化效果。结果表明:对于Pb(Ⅱ)、Cd(Ⅱ)污染土壤,土壤吸附量随pH升高而增加;在酸性条件下,SS促进土壤对Pb(Ⅱ)的吸附;在碱性条件下,FS促进土壤对Cd(Ⅱ)的吸附;同时SS与FS使土壤对Pb(Ⅱ)和Cd(Ⅱ)的解吸量大幅度降低。SS促进土壤对AsO-2的吸附,但该吸附量与pH变化无关;SS对AsO-2的解吸量影响不大,且该解吸量随pH升高而升高。SEM分析可知,FS与SS吸附重金属后形态变化显著。可见所用的环境材料对重金属Pb、Cd、As有明显的固化作用。

In order to investigate the solidification of environmental materials on heavy metals in contaminated soil, the adsorption-desorption tests of environmental materials zeolite （FS） and serpentine （SS） on lead （Pb）, cadmium （Cd） and arsenic （As） under different pH is conducted. The results show that the adsorption amount of Pb （ Ⅱ ） and Cd （ I] ） in contaminated soil increases with the growth of pH. SS contributes to adsorption of Pb（ Ⅱ ） under the acidic condition, while FS promotes the adsorption of Cd（ Ⅱ ） under the alkaline condition. SS and FS lead to a significant reduction in desorption of Pb（ Ⅱ ） and Cd（ Ⅱ）. SS promotes soil adsorption of AsOf , but the adsorption amount is not relevant to pH. The desorption amount of As02^- increases with pH growth, while it is not related to the existence of SS. SEM experiments illustrate significant morphological changes of FS and SS after absorbing heavy metals. Therefore, these environmental materials play important roles in heavy metal solidification.