Department of Earth and Planetary Science, The University of Tokyo , Bunkyo-ku, Tokyo 113-0033, Japan.
Advanced Science Research Center, Japan Atomic Energy Agency , Tokai, Ibaraki 319-1195, Japan.
Environ Sci Technol. 2017 Aug 15;51(16):9194-9201. doi: 10.1021/acs.est.7b01219. Epub 2017 Jul 26.
In the present study, we explore a new application of Barite (BaSO) as a sequestering phase for selenite (Se(IV)) and selenate (Se(VI)) ions from aqueous solutions because of the low solubility and high stability of Barite with its ability to selectively incorporate a large amount of various ions. The uptake of Se(IV) and Se(VI) during coprecipitation with Barite was investigated through batch experiments to understand the factors controlling effective removal of Se(IV) and Se(VI) from polluted water to Barite. The factors include (i) chemical affinity related to the degree of surface complexation between Barite surface and Se(IV)/Se(VI) ion and (ii) structural similarity related to the structural geometry of incorporated ions into the substituted site. The uptake of Se(IV) by Barite is dependent on pH, coexistent calcium ion, and sulfate concentration in the initial solution, possibly due to their effects on the chemical affinity and structural similarity. On the other hand, the uptake of Se(VI) by Barite was strongly dependent on sulfate concentration in the initial solution, which is only related to the structural similarity. This study describes the mechanisms for Se distribution between Barite and water, thereby providing a good estimate of its ability to effectively remove Se(IV) and Se(VI) from aqueous solutions under optimized experimental parameters examined here.
在本研究中，我们探索了重晶石 (BaSO) 的新应用，将其作为硒酸盐 (Se(IV)) 和硒酸盐 (Se(VI)) 离子从水溶液中沉淀的相，因为重晶石的低溶解度和高稳定性使其能够选择性地结合大量各种离子。通过批量实验研究了重晶石共沉淀过程中 Se(IV) 和 Se(VI) 的摄取，以了解控制有效去除污染水中 Se(IV) 和 Se(VI) 的因素，这些因素包括 (i) 与重晶石表面和 Se(IV)/Se(VI) 离子之间表面络合程度相关的化学亲和力，以及 (ii) 与掺入离子进入取代位置的结构几何形状相关的结构相似性。重晶石对 Se(IV) 的摄取取决于初始溶液中的 pH 值、共存钙离子和硫酸盐浓度，这可能是由于它们对化学亲和力和结构相似性的影响。另一方面，重晶石对 Se(VI) 的摄取强烈依赖于初始溶液中的硫酸盐浓度，这仅与结构相似性有关。本研究描述了重晶石与水之间 Se 分布的机制，从而在优化的实验参数下，对其有效去除水溶液中的 Se(IV) 和 Se(VI) 的能力进行了很好的估计。
