砷酸根促进红壤吸附Cd(Ⅱ)的机制  

EFFECT OF ARSENATE ON THE MECHANISM OF CADMIUM SORPTION ONTO A RED SOIL

作　　者：梁晶[1] 徐仁扣[2] 赵安珍[2] 谭文峰[1] 

机构地区：[1]华中农业大学资源与环境学院,武汉430070 [2]中国科学院南京土壤研究所土壤与农业可持续发展国家重点实验室,南京210008

出　　处：《环境化学》2007年第4期483-486,共4页Environmental Chemistry

基　　金：国家自然科学基金(40577054);国家重点基础规划项目(2002CB410808)资助

摘　　要：用一次平衡实验法研究砷酸根对Cd(Ⅱ)在红壤表面吸附和解吸的影响,结果表明,加入砷酸根使土壤对Cd(Ⅱ)的吸附量和解吸量均增加,且随着砷酸根加入量的增加,土壤对Cd(Ⅱ)的吸附增量和解吸增量也均增加·当向体系中加入砷酸根后,红壤胶体的Zeta电位显著降低,说明胶体颗粒表面的净负电荷增加·这说明砷酸根主要通过自身吸附增加了土壤表面的净负电荷,从而增加了土壤对Cd(Ⅱ)的静电吸附量·研究结果还表明,在pH3·5—6·0范围内,砷酸根均表现出对Cd(Ⅱ)吸附的显著促进作用,说明砷酸根与Cd(Ⅱ)在红壤表面的协同作用可以在比较宽的pH范围内发生.Effect of arsenate on adsorption and desorption of Cd （Ⅱ ） in a red soil was investigated with a batch experiment. The results showed that the presence of arsenate induced the increase in both adsorption and desorption of Cd（Ⅱ）, and the enhancement of arsenate increased with the increase in arsenate added. The addition of arsenate reduced the Zeta potential of colloid suspensions of the red Soil, which suggested that the negative charge on soil surface increased due to the presence of arsenate. The increase in negative surface charge resuhed in an apparent increase of Cd（ Ⅱ ） adsorption main mechanism for arsenate enhancement on Cd （ Ⅱ ） adsorp t through the electrostatic attraction and this is a tion by the soil. The results also indicated that arsenate enhanced Cd （ Ⅱ ） adsorption in the pH range from 3.5 to 6. 0 and suggested that co-sorption of arsenate and Cd （ Ⅱ ） on variable charge soils can occur in a wide range of pH.

关 键 词：砷酸根 Cd(Ⅱ) 吸附-解吸 红壤 

分 类 号：X131.3[环境科学与工程—环境科学]