砷酸盐在针铁矿上的界面作用过程及磷酸盐竞争吸附影响的试验和模拟研究

Interfacial Interactions between Arsenate and Goethite under the Influence of Competitive Adsorption of Phosphate

利用铁矿物吸附修复高砷地下水是环境领域的研究热点。通过试验和模拟对砷酸盐在针铁矿上的界面作用过程及磷酸盐的竞争吸附影响进行了研究。结果表明:砷酸盐和磷酸盐的吸附效果随pH值的增加而下降,在pH值大于针铁矿零点电位时,砷酸盐和磷酸盐的吸附效果随离子强度的增加而增加;砷酸盐在铁氧化物上的结合能力要强于磷酸盐,砷酸盐在针铁矿上的吸附形态主要以去质子化单核单齿的内层络合物>FeAsO2-4为主。最后,利用红外数据对砷酸盐的吸附机理进行了验证。

Remediation of high arsenic groundwater with iron minerals is a hotspot in the environmental research field.This paper studies the interfacial interactions of arsenate on the surface of goethite which may be impacted by the competitive adsorption of phosphate through lab experiments and modelling calculation.The results demonstrate that the amount of arsenate and phosphate adsorded on goethite decreases with the rise of pH value;high ionic strength is favorable to the adsorption of arsenate and phosphate onto goethite under the condition of pH value being higher than the zero potential of goethite;and the binding capacity of arsenate on iron oxide is stronger than that of phosphate.The arsenate adsorbed on goethite surfaces is primarily presented in the formation of mononuclear myonuclear complex>FeAsO2-4.Finally,the results of FTIR confirm the mechanism of arsenate adsorption onto goethite.