【摘要】 为了阐明生物炭和典型功能微生物希瓦氏菌MR-1(Shewanella oneidensis MR-1)在电子传递中的协同作用,以Cr(Ⅵ)污染土壤为载体,开展了电化学,动力学,电子传递路径识别等研究.结果表明,炭基菌剂对Cr(Ⅵ)污染土壤具有较好的修复效果,修复机制以MR-1对Cr(Ⅵ)的生物还原为主,符合双过程动力学模型.25mg/kg Cr(Ⅵ)含量,5%炭基菌剂投加量,30%土壤含水率时,炭基菌剂还原土壤Cr(Ⅵ)的效率最高,可达96.30%.吸附法炭基菌剂还原Cr(Ⅵ)迅速,但持续性能差;包埋法炭基菌剂还原Cr(Ⅵ)慢,但长期稳定发挥作用.生物炭作为微生物载体促进MR-1生长的同时,将MR-1表面的电子经由碳骨架传递至Cr(Ⅵ),提高了Cr(Ⅵ)还原效率.3个循环后炭基菌剂对Cr(Ⅵ)的还原率仍可达到60.44%,表明炭基菌剂在长期高效修复铬污染土壤方面有一定的应用前景.更多还原

【Abstract】 This study systematically investigated the synergistic interactions between biochar and the model electroactive microorganism Shewanella oneidensis MR-1 in electron transfer processes through comprehensive electrochemical analyses, kinetic modeling, and electron pathway characterization using chromium(Ⅵ)-contaminated soil as the experimental matrix. The biochar-based microbial agents demonstrated effective Cr(Ⅵ) bioremediation, with biological reduction mediated by MR-1identified as the predominant mechanism following dual-process kinetics. Optimal remediation performance(96.30% Cr(Ⅵ) reduction efficiency) was achieved under conditions of 25mg/kg Cr(Ⅵ) contamination, 5%(w/w) biochar-based microbial agents dosage, and 30% soil moisture content. Comparative analysis revealed distinct temporal remediation patterns: adsorption-based biochar-microbial composites exhibited rapid initial Cr(Ⅵ) sequestration but limited long-term stability, whereas encapsulation-based formulations showed gradual but sustained reduction capacity. Mechanistic studies demonstrated that biochar functioned as an effective microbial carrier, simultaneously enhancing MR-1proliferation and facilitating extracellular electron transfer from microbial cells to Cr(Ⅵ) contaminants through its conductive carbon matrix. Notably, the immobilized system maintained 60.44% reduction efficiency after three operational cycles, highlighting its potential for sustainable in situ remediation of chromium-contaminated soils.更多还原