低分子有机酸对砷在水土环境中吸附/解吸作用的影响

Effects of low molecular organic acids on the adsorption and desorption of arsenic in soil and water environment

以As(Ⅲ)为外砷污染源,采用平衡吸附法研究了两种低分子有机酸(草酸、柠檬酸)对砷在土壤中吸附/解吸行为的影响及作用机制。实验结果表明:空白土壤对砷的等温吸附符合Langmuir方程,热力学实验表明吸附为自发进行,动力学吸附过程符合准二级动力方程;在两种低分子有机酸条件下,土壤对砷的吸附量与有机酸浓度呈现一定的正相关;强酸、强碱条件对吸附具有一定的抑制作用,草酸对土壤吸附/解吸的影响大于柠檬酸。

In this paper,arsenic(Ⅲ)was taken as the pollution sources,under different conditions for the adsorption and desorption the effect behavior and mechanism of the two kinds of low molecular organic acids(oxalic acid,citric acid)were studied using the equilibrium method.The results showed that the adsorption of arsenic in blank soil was in accordance with the Langmuir equation,while the thermodynamic experiments was spontaneous,and the kinetic adsorption process was in accordance with the quasi-second-order dynamic equation.In the presence of two kinds of low molecular acid,the adsorption amount of arsenic in soil was positively correlated with the concentration of organic acid.The adsorption was inhibited by strong acid or alkaline environment,and the adsorption and desorption of oxalic acid was greater than that of citric acid.