Abstract：
Iron minerals, which exert excellent biocompatibility and reactivity with redox-active microorganisms, have attracted attention as a precursor to synthesizing composite materials with higher catalytic efficiency in driving redox-active microorganisms to reduce Cr(VI). However, researches on the effective preparation method of composites, the interaction between bacteria and composite materials and the mechanism of electron transfer are still scarce. In this work, Fe-complex@BC prepared by a one-step method using goethite was used for chromium treatment together with soil microorganisms. The composite was the best-performing in promoting Cr(VI) bioreduction (up to 3.48 mg (L·h)-1) than Fe-complex (2.26 mg (L·h)-1) and biochar (0.5 mg (L·h)-1), even about 19 times higher than that of bioreduction without materials. Specifically, Fe-complex@BC shortened the electron transfer distance due to its excellent adsorption properties for bacteria and Cr(VI). Its high redox activity also promoted Cr(VI) bioreduction by directly enhancing electron transfer. In addition, the presence of the Fe(III)/Fe(II) cycle proved that the active sites of composite could be regenerated to reduce Cr(VI) persistently by receiving extracellular electrons from bacteria. High-throughput 16 S rDNA gene sequencing indicated the composite could promote the proliferation of electrochemically active bacteria, which directly enhanced bioreduction. This study developed the low-cost Fe@BC material prepared by a one-step co-pyrolysis method, which exerts a synergistic effect with soil microorganisms and presents a promising potential for chromium pollution treatment.
摘要：
铁矿物,与氧化还原活性微生物具有优异的生物相容性和反应性，作为合成具有较高催化效率的复合材料的前体，在驱动氧化还原活性微生物还原Cr（VI）方面引起了关注。然而,研究复合材料的有效制备方法，细菌与复合材料之间的相互作用和电子转移机制仍然很少。在这项工作中,通过使用针铁矿的一步法制备的Fe-络合物@BC与土壤微生物一起用于铬处理。该复合材料在促进Cr（VI）生物还原（高达3.48mg（L·h）-1）方面的性能优于Fe配合物（2.26mg（L·h）-1）和生物炭（0.5mg（L·h）-1），甚至比没有材料的生物还原高出约19倍。具体来说,Fe配合物@BC由于其对细菌和Cr（VI）的优异吸附性能，缩短了电子转移距离。其高氧化还原活性还通过直接增强电子转移来促进Cr（VI）的生物还原。此外,Fe（III）/Fe（II）循环的存在证明，复合材料的活性位点可以通过从细菌接收胞外电子而持续再生以还原Cr（VI）。高通量16SrDNA基因测序表明，该复合物能促进电化学活性细菌的增殖，直接增强了生物还原。本研究开发了通过一步共热解方法制备的低成本Fe@BC材料，它与土壤微生物发挥协同作用，并为铬污染处理提供了有希望的潜力。
