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首页> 外文期刊>Quantum Beam Science >Analysis of Cr(VI) Bioremediation by Citrobacter freundii Using Synchrotron Soft X-ray Scanning Transmission X-ray Microscopy
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Analysis of Cr(VI) Bioremediation by Citrobacter freundii Using Synchrotron Soft X-ray Scanning Transmission X-ray Microscopy

机译：使用Synchrotron软X射线扫描透射X射线显微镜分析CR（VI）Bioremiation的Cr（vi）生物修复

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Scanning transmission X-ray microscopy (STXM) was utilized for analysing the bioremediation of Cr(VI) by Citrobacter freundii, a species of gram-negative bacteria. The biosorption and bioreduction processes were analysed by the chemical mapping of cells biosorbed at different concentrations of Cr(VI). STXM spectromicroscopy images were recorded at O K-edge and Cr L-edge. A thorough analysis of the X-ray absorption features corresponding to different oxidation states of Cr in the biosorbed cell indicated the coexistence of Cr(III) and Cr(VI) at higher concentrations. This signifies the presence of partially reduced Cr(VI) in addition to biosorbed Cr(VI). In addition, the Cr(III) signal is intense compared with Cr(VI) at different regions of the cell indicating excess of reduced Cr. Speciation of adsorbed Cr was analysed for the spectral features of biosorbed cell and comparison with Cr standards. Analysis of absorption onset, L3/L2 ratio and absorption fine structure concludes that adsorbed Cr is predominantly present as Cr(III) hydroxide or oxyhydroxide. The evolution of absorption features in the duration of biosorption process was also studied. These time lapse studies depict the gradual decrement in Cr(VI) signal as biosorption proceeds. A strong evidence of interaction of Cr with the cell material was also observed. The obtained results provide insights into the biosorption process and chemical speciation of Cr on the cells.
机译：扫描透射X射线显微镜（STXM）用于分析CRORBORACTRE FREUNDII的CR（VI）的生物化，一种革兰氏阴性细菌。通过在不同浓度Cr（VI）的细胞的化学映射分析生物吸附和生物诱发方法。 STXM SpectromicRoscopy图像被记录在O K-Edge和Cr L边缘。对对应于生物吸附细胞中Cr的不同氧化态的X射线吸收特征的彻底分析表明Cr（III）和Cr（VI）在较高浓度下的共存。除了生物吸收的Cr（VI）之外，这表示存在部分减少的Cr（VI）。另外，与细胞的不同区域的Cr（vi）相比，Cr（iii）信号与表明过量减少的Cr的Cr（vi）进行剧烈。分析了吸附的CR的物质，用于生物吸收细胞的光谱特征，并与Cr标准进行比较。吸收发作的分析，L3 / L2比和吸收细结构得出结论，吸附的Cr主要作为Cr（III）氢氧化物或羟基氧化物。还研究了生物吸附过程持续时间中吸收特征的演变。这些时间流逝研究描绘了作为生物吸收的Cr（VI）信号的逐渐减少。还观察到Cr与细胞材料相互作用的强大证据。所得结果提供了对细胞上Cr的生物吸附过程和化学物质的见解。

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