Geologic Environment Division, Korea Institute of Geoscience and Mineral Resources, 124 Gwahak-ro, Yuseong-gu, Daejeon, 34132, Republic of Korea.
Department of Energy & Resources Engineering, Korea Maritime and Ocean University, 727 Taejong-ro, Yeongdo-Gu, Busan, 49112, Republic of Korea.
Chemosphere. 2018 Mar;195:762-770. doi: 10.1016/j.chemosphere.2017.12.133. Epub 2017 Dec 26.
This study examined the reaction mechanism of arsenite, As(III), and antimonite, Sb(III), with iron sulfide and compared their pH-dependent reaction behaviors under strictly anoxic environments. The comparison of Sb(III) with As(III), based on their chemical similarity, may provide useful insight into understanding the geochemical behavior of the less studied Sb(III). The pH-dependent batch sorption studies revealed that As(III) and Sb(III) displayed similar removal trends with pH in terms of the removal efficiency. However, the aqueous As(III) species transformed to thioarsenite species, while aqueous Sb(III) species remained inert under the highly sulfidic anoxic system. An X-ray absorption spectroscopy study demonstrated the reaction of As(III) and Sb(III) at acidic pH was closely related to the precipitation of sulfide minerals AsS and SbS, respectively, as a consequence of the reaction with sulfide produced through mackinawite dissolution. Meanwhile, the removal at basic pH was inferred as a surface reaction, possibly through surface complexation, surface-precipitation, or both. In this study, the pH-dependent Sb(III) uptake mechanisms proved to be similar to the corresponding mechanisms for As(III) uptake, with mackinawite demonstrating a superior capacity to scavenge Sb(III) in ferrous and sulfide-rich reducing environments.
本研究考察了亚砷酸盐（As(III)）和锑酸盐（Sb(III)）与硫化亚铁的反应机制，并在严格的缺氧环境下比较了它们随 pH 值变化的反应行为。基于化学相似性，将 Sb(III)与 As(III)进行比较，可能有助于深入了解研究较少的 Sb(III)的地球化学行为。pH 值依赖的批处理吸附研究表明，As(III)和 Sb(III)在去除效率方面表现出相似的随 pH 值变化的去除趋势。然而，在高度硫化缺氧体系下，水合 As(III)物种转化为硫代砷酸盐物种，而水合 Sb(III)物种保持惰性。X 射线吸收光谱研究表明，在酸性 pH 下，As(III)和 Sb(III)的反应与通过 mackinawite 溶解产生的硫化物反应分别密切相关，导致形成硫化物矿物 AsS 和 SbS。同时，碱性 pH 下的去除被推断为表面反应，可能通过表面络合、表面沉淀或两者共同作用。在本研究中，pH 值依赖的 Sb(III)摄取机制被证明与相应的 As(III)摄取机制相似，mackinawite 在亚铁和富含硫化物的还原环境中具有更强的捕获 Sb(III)的能力。
