School of Metallurgy and Environment, Central South University, Changsha 410083, China; Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Changsha 410083, China.
School of Metallurgy and Environment, Central South University, Changsha 410083, China.
Chemosphere. 2017 Sep;182:595-604. doi: 10.1016/j.chemosphere.2017.05.018. Epub 2017 May 3.
Aqueous complexes between ferric (Fe(III)) and arsenate (As(V)) are indispensable for understanding the mobility of arsenic (As) in Fe(III)-As(V)-rich systems. In this study, aqueous Fe(III)-As(V) complexes, FeHAsO and FeHAsO, were postulated based on the qualitative analysis of UV-Vis spectra in both Fe(III)-As(V)-HClO and Fe(III)-As(V)-HSO systems. Subsequently, monodentate structures were evidenced by Fe K-edge EXAFS and modeled as [FeHAsO(HO)] and [FeHAsO(HO)] by DFT. The feature band at ∼280 nm was verified as electron excitation chiefly from Fe-As-bridged O atoms to d-orbital of Fe in [FeHAsO(HO)] and [FeHAsO(HO)]. The structural and spectral information of Fe(III)-As(V) complexes will enable future speciation analysis in Fe(III)-As(V)-rich system.
铁(Fe(III))和砷酸盐(As(V))的水合配合物对于理解富铁(III)-砷(V)系统中砷的迁移性是必不可少的。在这项研究中，基于 Fe(III)-As(V)-HClO 和 Fe(III)-As(V)-HSO 体系中紫外可见光谱的定性分析，假设了水合 Fe(III)-As(V)配合物 FeHAsO 和 FeHAsO。随后，通过 Fe K 边 EXAFS 证实了其具有单价配位结构，并通过 DFT 将其模拟为[FeHAsO(HO)]和[FeHAsO(HO)]。约 280nm 的特征带被证实为电子激发，主要来自[FeHAsO(HO)]和[FeHAsO(HO)]中 Fe-As 桥连 O 原子到 Fe 的 d 轨道。Fe(III)-As(V)配合物的结构和光谱信息将有助于未来对富铁(III)-砷(V)系统中的形态分析。
