pH和磷酸根对砷(Ⅴ)在棕壤上吸附解吸的影响

Effect of Phosphate on Arsenate Adsorption by Brown Soil

研究了pH以及As(Ⅴ)、P的加入顺序和P浓度对As(Ⅴ)和P在棕壤上吸附的影响。结果表明,As(Ⅴ)和P的加入顺序对其在棕壤上的吸附影响很大。As(Ⅴ)和P在棕壤上的吸附表现为相互抑制。在As(Ⅴ)和P共同存在的体系中,As(Ⅴ)对P吸附的抑制率要大于P对As(Ⅴ)的抑制。当P/As较低(P/As<5)时,P浓度的增加会明显降低土壤对As(Ⅴ)的吸附,As(Ⅴ)的解吸量随P浓度的提高迅速增加;而当P/As>5时,As(Ⅴ)解吸量的增加趋于缓慢。

The effect of pH,the anion addition order and the anion concentration of arsenate （As） and phosphate （P） on the competitive adsorption of As and P in brown soils was investigated. The results show that the order of anion addition strongly influenced the adsorption of arsenate and phosphate in soils. The efficiency of arsenate in inhibiting the adsorption of phosphate on brown soils was greater than that of phosphate in reducing the arsenate adsorption when arsenate and phosphate were added as a mixture. The presence of increasing concentrations of phosphate caused a reduction in arsenate adsorption obviously at As/P molar ratio〈5. We also found the percentage of desorption of arsenate had a sharp increase in the presence of increasing concentration of phosphate when the P/As molar ratio〉5,and after that the increase was not obviously.