Structural and compositional evolution of Cr/Fe solids after indirect chromate reduction by dissimilatory iron-reducing bacteria
Structural and compositional evolution of Cr/Fe solids after indirect chromate reduction by dissimilatory iron-reducing bacteria
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DOI：
10.1016/s0016-7037(02)01081-5
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发表时间：
2003-02-01
影响因子：
5
通讯作者：
Fendorf, SR
中科院分区：
文献类型：
--
作者：
Hansel, CM;Wielinga, BW;Fendorf, SR
Cr（VI）还原为Cr（III）降低了Cr在地表和地下环境中的迁移率和毒性。六价铬的还原可以通过化学或生物方法进行。耦合过程也可能发生，包括通过生产微生物代谢物，包括水铁（II）的还原。Cr（VI）还原的最终途径将决定反应产物，从而决定Cr（III）的溶解度。在这里，我们研究了铁还原条件下铬酸盐的生物-非生物耦合还原途径对Cr的影响。两线水合铁的异化细菌还原通过产生水铁（II）间接刺激Cr（VI）的还原。该反应的产物是通式为Fe1-x，Cr-x(OH)(3)的铁(il)-铬（III）氢氧化物混合物。nH(2)O，具有α / β - feooh局域序。随着反应的进行，系统内的Fe被循环（即氢氧化物反应产物中的Fe（III）被异化的铁还原菌进一步还原为Fe(II)，可用于继续还原Cr），并且氢氧化物产物相对于Fe变得富集Cr，最终接近纯Cr(OH)(3) nH(2)O相。尽管纯相的氢氧化铬相对来说是不溶的，但这种铬净化过程明显地增加了氢氧化铬相的溶解度。版权所有爱思唯尔科学有限公司
The mobility and toxicity of Cr within surface and subsurface environments is diminished by the reduction of Cr(VI) to Cr(III). The reduction of hexavalent chromium can proceed via chemical or biological means. Coupled processes may also occur including reduction via the production of microbial metabolites, including aqueous Fe(II). The ultimate pathway of Cr(VI) reduction will dictate the reaction products and hence the solubility of Cr(III). Here, we investigate the fate of Cr following a coupled biotic-abiotic reduction pathway of chromate under iron-reducing conditions. Dissimilatory bacterial reduction of two-line ferrihydrite indirectly stimulates reduction of Cr(VI) by producing aqueous Fe(II). The product of this reaction is a mixed Fe(Ill)-Cr(III) hydroxide of the general formula Fe1-x,Cr-x(OH)(3) . nH(2)O, having an alpha/beta-FeOOH local order. As the reaction proceeds, Fe within the system is cycled (i.e., Fe(III) within the hydroxide reaction product is further reduced by dissimilatory iron-reducing bacteria to Fe(II) and available for continued Cr reduction) and the hydroxide products become enriched in Cr relative to Fe, ultimately approaching a pure Cr(OH)(3) nH(2)O phase. This Cr purification process appreciably increases the solubility of the hydroxide phases, although even the pure-phase chromium hydroxide is relatively insoluble. Copyright (C) 2003 Elsevier Science Ltd.