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首页> 外文期刊>Environmental Science & Technology >Microbial selenate sorption and reduction in nutrient limited systems
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Microbial selenate sorption and reduction in nutrient limited systems

机译：养分有限系统中微生物硒酸盐的吸附和减少

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In this study, batch sorption experiments and X-ray adsorption spectroscopy (XAS) were utilized to investigate selenate sorption onto Shewanella putrefaciens 200R. Selenate sorption was studied as a function of pH (ranging from 3 to 7), ionic strength (ranging from 0.1 to 0.001 M), and initial selenate concentration (ranging from 10 to 5000 AM) in the absence of external electron donors. The results show that the extent of selenate sorption is strongly dependent on pH and ionic strength, with maximum sorption occurring at low pH (pH = 3) and low ionic strength (0.001 M NaCl) conditions. The strong dependence of Se sorption with ionic strength suggests the formation of outer-sphere complexes with the cell wall functional groups. Langmuir isotherm plots yielded log K-ads values from 2.74 to 3.02. Desorption experiments demonstrated that the binding of selenate onto S. putrefaciens was not completely reversible. XANES analysis of the cells after sorption experiments revealed the presence of elemental selenium, indicating that S. putrefaciens has a capacity to reduce Se(VI) to Se(0) in the absence of external electron donors. We conclude that Se sorption onto S. putrefaciens cell walls is the result of the combination of outer-sphere complexation and cell surface reduction. This sorption process leads to a complex reservoir of bound Se which is not entirely reversible.
机译：在这项研究中，分批吸附实验和X射线吸收光谱（XAS）被用来研究硒酸盐在Shewanella putrefaciens 200R上的硒酸盐吸附。在没有外部电子供体的情况下，研究了硒酸盐的吸附随pH（3至7），离子强度（0.1至0.001 M）和初始硒酸盐浓度（10至5000 AM）的变化。结果表明，硒酸根的吸附程度强烈依赖于pH和离子强度，在低pH（pH = 3）和低离子强度（0.001 M NaCl）条件下发生最大吸附。硒吸附与离子强度的强相关性表明与细胞壁官能团形成的外球复合物。 Langmuir等温线图得出的log K-ads值从2.74到3.02。解吸实验表明，硒酸盐与腐霉链球菌的结合不是完全可逆的。吸附实验后对细胞的XANES分析显示元素硒的存在，表明腐烂链球菌具有在没有外部电子供体的情况下将Se（VI）还原为Se（0）的能力。我们得出的结论是，硒在腐霉链球菌细胞壁上的吸附是外球络合和细胞表面还原相结合的结果。这种吸附过程导致了一个复杂的结合硒储集层，它不是完全可逆的。

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