有机物对重金属在粘土中吸附行为的影响

实验选用填埋场垃圾降解过程中“产酸阶段”和“产甲烷阶段”产生的己酸和腐殖酸及重金属 Cd、Pb、Ni、Zn和 Mn为研究对象 ,研究有机物存在对粘土吸附重金属的影响 .结果表明 :粘土对纯重金属的吸附随着溶液 p H值升高而增强 ;对己酸的吸附随着溶液 p H值升高而增强 ,对腐殖酸的吸附随着溶液 p H值升高而减弱 .当溶液中己酸和重金属共存时 ,由于竞争吸附使得粘土对重金属的吸附能力普遍有较小幅度的下降 ;当溶液中存在腐殖酸和重金属共存时 ,粘土对重金属的吸附能力增强 ,主要是由于酸性条件下富里酸发生解离后与重金属络合 ,其络合物与粘土颗粒有一定的结合能力 ,增强了粘土对重金属的吸附能力 .

Effect of Organic Acids on Heavy Metal Migration in Clay

The organic acids resulting from the waste degradation process in the landfill and heavy metal ions are chosen as the research model.The adsorption experiments show that the adsorption of pure heavy metal and hexanoic acid by clay increases with an increase of pH and that of humic acid by clay decreases with pH increase.When hexanoic acid and heavy metal ions coexist in the solution,the adsorption of metal ions by clay tends to decrease because of the competitive adsorption of hexanoic acid.However.the presence of humic can enhance the adsorption of heavy metal ions because of its complexation with metal inos after dissociation in acidic condition.