Yan Li, Chan Tingshan, Jing Chuanyong
State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan.
Environ Sci Technol. 2022 Mar 1;56(5):3138-3146. doi: 10.1021/acs.est.1c07801. Epub 2022 Feb 9.
Heterogeneous reactions at the mineral-water interface are of paramount importance in controlling the transport of contaminants. Herein, antimony (Sb) adsorption and subsequent precipitation on FeO facets were explored to understand its partitioning mechanisms by multiple complementary techniques. Our extended X-ray absorption fine structure spectroscopy and density functional theory results provided a consensus on the local coordination environment of Sb(III) and Sb(V) on FeO facets. We observed that Sb adsorption and the following precipitation are associated with both Sb concentrations and FeO facets, and a change in the Sb surface-binding mode from edge-sharing to corner-sharing is preferred in precipitation. FeO facets determine Sb binding structures, resulting in a facet-dependent transformation of adsorption to precipitation. The preferred corner-sharing complexes on the {001} facet facilitated the formation of SbO and NaSb(OH) precipitates at a lower Sb concentration compared with other two {110} and {214} facets. In addition, the facet-specific binding configuration renders a heterogeneous epitaxial growth of SbO. Our study provides a molecular understanding of facet effects on Sb adsorption and precipitation on minerals.
矿物 - 水界面的非均相反应在控制污染物迁移方面至关重要。在此，通过多种互补技术研究了锑（Sb）在FeO晶面上的吸附及随后的沉淀，以了解其分配机制。我们的扩展X射线吸收精细结构光谱和密度泛函理论结果对FeO晶面上Sb(III)和Sb(V)的局部配位环境达成了共识。我们观察到Sb的吸附及其后的沉淀与Sb浓度和FeO晶面均相关，并且在沉淀过程中，Sb表面结合模式从边共享到角共享的变化是优选的。FeO晶面决定了Sb的结合结构，导致吸附到沉淀的晶面依赖性转变。与其他两个{110}和{214}晶面相比，{001}晶面上优选的角共享配合物在较低的Sb浓度下促进了SbO和NaSb(OH)沉淀的形成。此外，晶面特异性结合构型使得SbO发生异质外延生长。我们的研究提供了对晶面效应在矿物上Sb吸附和沉淀方面的分子理解。
