电子介导下铁基硫化物协同电活性铬还原菌矿化固定Cr(VI)及其微观机制的研究

微生物法在处理土壤中六价铬方面占有重要的优势，但其过程受限于外源电子供体的供给，成为影响微生物对六价铬矿化固定的关键因素。本项目使用生物电化学系统中阳极提供的清洁的外源电子供体，通过调控电子介导过程，研究生物膜中铬还原菌对迁移态铬还原和固定的影响，建立微生物基于外源电子还原Cr(VI)成矿的研究体系。重点探究此过程中微生物表面有机官能团的变化，分析参与固定铬的有机官能团及配位方式；进一步分析复合生物膜中铁基硫化物协同铬还原菌对迁移态铬还原和固定的影响及矿化过程中产生的铬铁矿物的微观形态、结构及物相演变规律，并结合微生物表面官能团变化信息，阐明铁基硫化物在微生物对六价铬还原和固定过程中的协同机制。最终将揭示电子介导下铁基硫化物协同微生物矿化固定Cr(VI)的原理，不仅将有助于深入理解自然界中微生物基于外源电子还原Cr(VI)成矿过程，也为铬污染物在土壤环境中的形成、演变提供重要的理论依据。

Microbiological method has an important advantage in the treatment of hexavalent chromium (Cr(VI)) in soil, but its process is limited by the supply of exogenous electron donors. It becomes the key factor affecting the mineralization and fixation of Cr(VI) by microorganisms. This project utilizes the clean exogenous electron donors provided by the anode in the bioelectrochemical system to study the influence of chromium reducing bacteria in the biofilm on the reduction and fixation of migrating chromium by regulating the electron-mediated process, so as to establish a research system of biological Cr(VI) reduction mineralization based on exogenous electrons. The change of organic functional groups on the surface of microorganism in biofilm during this process is studied with emphasis, and the organic functional groups and coordination modes that participate in the fixation of chromium are analyzed; Further analysis of the synergy between iron based sulfide in the composite biofilm and chrome-reducing bacteria on the reduction and fixation of migrating chromium and the microscopic morphology, structure and phase evolution of chromite produced in the mineralization process. Combining the change information of obtained microbial surface functional groups, the synergistic mechanism of iron-based sulfides in microbial reduction and fixation of Cr(VI) is elucidated. This project will eventually reveal the principles of Cr(VI) immobilization under the synergistic effect of electron-mediated iron based sulfide and microorganisms, which will not only benefit the understanding of the mineralization process of Cr(VI) reduction by microorganisms based on exogenous photoelectron in nature, but also provide an important theoretical basis for the formation and evolution of chromium pollutants in the soil environment.