College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; State Key Laboratory of Pollution Control and Resources Reuse, Tongji University, Shanghai 200092, China.
Department of Civil and Environmental Engineering, University of California, Los Angeles, CA 90095, USA.
Chemosphere. 2019 Apr;221:793-801. doi: 10.1016/j.chemosphere.2019.01.039. Epub 2019 Jan 7.
In this study, the removal of Cr (VI) was examined in the presence of bio-produced Fe (II) from hematite, sulfate and dissolved organic matter by Geobacter sulfurreducens. The adaptation results of G. sulfurreducens showed that cells growth was stimulated up to 576 μM of Cr (VI) concentration. The first-order rate and electron transfer rate in each step during Cr (VI) reduction by G. sulfurreducens in the presence of hematite was clearly modeled and calculated. For Cr (VI) reduction rate, both separately dissolved and adsorbed bio-produced Fe (II) were faster than G. sulfurreducens although bio-produced Fe (II) contributed only 20% to total Cr (VI) removal in a combined system containing Cr (VI), hematite and G. sulfurreducens. The electron transfer rate from G. sulfurreducens to hematite (R) to produce Fe (II) was a limited step and electron transfer rate from acetate to Cr (VI) (1.8 μeq L h) by G. sulfurreducens was much higher than that to hematite (0.272 μeq L h, producing Fe (II)). Cr (VI) reduction was enhanced in the presence of SO due to sulfate boost cells growth. AQDS enhanced Cr (VI) reduction by serving as an electron shuttle thus accelerating the electron transfer rate.
在这项研究中，研究了在赤铁矿、硫酸盐和溶解有机物存在的情况下，脱硫弧菌产生的生物 Fe(II)对六价铬（Cr(VI)）的去除作用。脱硫弧菌的适应结果表明，细胞生长受到高达 576μM 的 Cr(VI)浓度的刺激。在赤铁矿存在的情况下，通过脱硫弧菌还原 Cr(VI)的各个步骤中的一级反应速率和电子传递速率得到了明确的建模和计算。对于 Cr(VI)的还原速率，单独溶解的和吸附的生物产生的 Fe(II)都比脱硫弧菌更快，尽管在包含 Cr(VI)、赤铁矿和脱硫弧菌的组合系统中，生物产生的 Fe(II)仅占总 Cr(VI)去除量的 20%。从脱硫弧菌到赤铁矿（R）产生 Fe(II)的电子传递速率是一个限制步骤，而脱硫弧菌从乙酸盐到 Cr(VI)的电子传递速率（1.8μeq L h）远高于到赤铁矿的电子传递速率（0.272μeq L h，产生 Fe(II)）。由于硫酸盐促进细胞生长，SO 的存在增强了 Cr(VI)的还原。AQDS 作为电子穿梭体，促进 Cr(VI)的还原，从而加速电子传递速率。
