作 者：Jiang, X.L., Peng, C.J., Fu, D., Chen, Z., Shen,L., Li, Q.B.,Ouyang, T., and Wang, Y.P. 影响因子：2.800

刊物名称：Applied Surface Science

出版年份：2015

卷:353页:1087-1094

In this study, macroscopic and spectroscopic experimental methods accurately modeled the sorption process of arsenate on ferrihydrite. EXAFS, X-ray diffraction and infrared (IR) spectroscopy indicated that the behavior of As(V) adsorption onto ferrihydrite took place mainly via surface complexation and surface precipitation at acidic pH (3.0–6.0), while the surface precipitation was dominated at longer time intervals and higher Fe³⁺concentration. The macroscopic competitive adsorption experiment between arsenate with phosphate indicated two types of adsorption sites existing on the surface of ferrihydrite, i.e., non-exchangeable sites, which are responsible for a rapid surface complex formation; and exchangeable sites for a slow build-up of surface precipitates. In the slow build-up precipitates, the As(V) surface coverage(mmol/g) exhibited a good linear relationship (R²= 0.952) with the amount of dissolved Fe³⁺. Three steps are involved during the process of surface precipitation, i.e., (1) an initial uptake of As(V) via surface complexation; (2) re-adsorption of Fe³⁺leaching from ferrihydrite on the surface complex; and (3) As(V)adsorption via surface complexation again and finally forming the surface precipitate.

Fig.3.(a)As K-edge XANES spectra of As (V) adsorption by ferrihydrite (pH3.0–9.0) compared to reference FeAsO₄; (b)Corresponding radial structure functions(RSF).