Continuous-flow iron and bio-iron columns were used to evaluate the effects of seepage velocity and concentration on Cr(VI) removal from groundwater. Solid-phase analysis showed that microorganisms accelerated iron corrosion by excreting extracellular polymeric substances and generated highly reactive minerals containing Fe(II), which gave the bio-iron column a longer life span and enhanced capacity for Cr(VI) removal via enhanced adsorption and reduction by reactive minerals. The bio-iron column showed much higher Cr(VI) removal capacity than the iron column with increasing Cr(VI) loading, which was obtained by increasing the seepage velocity or influent Cr(VI) concentration from 95 to 1138 m yr-1 and from 5 to 40 mg L-1 , respectively. When the Cr(VI) loading varied in a range of 0 to 10 mg L-1 h-1 , the bio-iron column had a 60% longer longevity and one- to sixfold higher Cr(VI) elimination capacity than the iron column. This result indicated that, under fluctuating hydraulic conditions [e.g., seepage velocity and Cr(VI) concentration], the presence of microorganisms can significantly boost Cr(VI) removal using Fe0 -based permeable reactive barriers.

中文翻译：

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渗流速度和浓度对非生物和生物铁柱中六价铬去除的影响

连续流动铁柱和生物铁柱用于评估渗流速度和浓度对从地下水中去除 Cr(VI) 的影响。固相分析表明，微生物通过排泄胞外聚合物加速铁腐蚀，并产生含有 Fe(II) 的高活性矿物质，这使生物铁柱具有更长的寿命和通过增强吸附和去除 Cr(VI) 的能力。活性矿物还原。随着 Cr(VI) 负载量的增加，生物铁柱表现出比铁柱高得多的 Cr(VI) 去除能力，这是通过将渗流速度或进水 Cr(VI) 浓度从 95 m yr-1 增加到 1138 m yr-1 和分别为 5 至 40 mg L-1。当 Cr(VI) 负载量在 0 到 10 mg L-1 h-1 范围内变化时，与铁柱相比，生物铁柱的使用寿命长 60%，Cr(VI) 消除能力高出一到六倍。该结果表明，在波动的水力条件下[例如，渗流速度和 Cr(VI) 浓度]，微生物的存在可以使用 Fe0 基渗透性反应屏障显着促进 Cr(VI) 的去除。