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首页> 外文期刊>Environmental Science & Technology >Development of a biosorbent for arsenite: Structural modeling based on X-ray spectroscopy
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Development of a biosorbent for arsenite: Structural modeling based on X-ray spectroscopy

机译：砷的生物吸附剂的开发：基于X射线光谱的结构模型

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This work describes a biological route for direct sorption of aqueous As(III) species, which are the most toxic and mobile arsenic species found in soils. Based upon the biochemical mechanisms that explain arsenic toxicity, we propose that a waste biomass with a high fibrous protein content obtained from chicken feathers can be used for selective As(III) adsorption. Prior to adsorption, the disulfide bridges present in the biomass are reduced by thioglycolate. Our investigations demonstrated that As(III) is specifically adsorbed on the biomass and, contrary to the behavior observed with inorganic sorbents, the lower is the pH the more effective is the removal. Arsenic uptake reaches values of up to 270 mumol As(III)/g of biomass. Analyses by synchrotron light techniques, such as XANES, demonstrated that arsenic is adsorbed in its trivalent state, an advantage over conventional techniques for As uptake, which usually require a previous oxidation stage. EXAFS analyses showed that each As atom is directly Pound to three S atoms with an estimated distance of 2.26 Angstrom. The uptake mechanism is explained in terms of the structural similarities between the As(III)-biomass complex structure and that of arsenite ions and Ars-Operon system encoded proteins and phytochelatins. The biological route presented here offers the perspective of a direct removal of arsenic in its reduced form.
机译：这项工作描述了一种直接吸附含水As（III）物种的生物学途径，As（III）是在土壤中发现的最具毒性和移动性的砷物种。基于解释砷毒性的生化机制，我们建议从鸡毛获得的纤维蛋白含量高的废生物质可用于选择性As（III）吸附。在吸附之前，生物质中存在的二硫键被巯基乙酸盐还原。我们的研究表明，As（III）专门吸附在生物质上，与无机吸附剂观察到的行为相反，pH值越低，去除效果越好。砷的吸收量高达每克生物质270摩尔MoAs（III）。通过同步加速器光技术（例如XANES）进行的分析表明，砷以其三价态被吸附，这比常规的砷吸收技术具有优势，后者通常需要先前的氧化步骤。 EXAFS分析表明，每个As原子都直接与三个S原子相连，估计距离为2.26埃。根据As（III）-生物质复杂结构与砷离子和Ars-Operon系统编码的蛋白质和植物螯合素之间的结构相似性来解释摄取机理。本文介绍的生物途径为直接去除还原形式的砷提供了前景。

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