Niu Shixin, Li Changsuo, Gao Shuai, Tian Jingya, Zhang Chao, Li Lixia, Huang Yao, Lyu Honghong
Shandong Provincial Geo-mineral Engineering Exploration Institute, Shandong Provincial Bureau of Geology & Mineral Resources, Jinan, China.
Shandong Engineering Research Center for Environmental Protection and Remediation on Groundwater, Jinan, China.
Front Microbiol. 2024 Jul 18;15:1443682. doi: 10.3389/fmicb.2024.1443682. eCollection 2024.
Dehalogenating bacteria are still deficient when targeted to deal with chlorinated hydrocarbons (CHCs) contamination: e.g., slow metabolic rates, limited substrate range, formation of toxic intermediates. To enhance its dechlorination capacity, biochar and its composites with appropriate surface activity and biocompatibility are selected for coupled dechlorination. Because of its special surface physical and chemical properties, it promotes biofilm formation by dehalogenating bacteria on its surface and improves the living environment for dehalogenating bacteria. Next, biochar and its composites provide active sites for the removal of CHCs through adsorption, activation and catalysis. These sites can be specific metal centers, functional groups or structural defects. Under microbial mediation, these sites can undergo activation and catalytic cycles, thereby increasing dechlorination efficiency. However, there is a lack of systematic understanding of the mechanisms of dechlorination in biogenic and abiogenic systems based on biochar. Therefore, this article comprehensively summarizes the recent research progress of biochar and its composites as a "Taiwan balm" for the degradation of CHCs in terms of adsorption, catalysis, improvement of microbial community structure and promotion of degradation and metabolism of CHCs. The removal efficiency, influencing factors and reaction mechanism of the degraded CHCs were also discussed. The following conclusions were drawn, in the pure biochar system, the CHCs are fixed to its surface by adsorption through chemical bonds on its surface; the biochar composite material relies on persistent free radicals and electron shuttle mechanisms to react with CHCs, disrupting their molecular structure and reducing them; biochar-coupled microorganisms reduce CHCs primarily by forming an "electron shuttle bridge" between biological and non-biological organisms. Finally, the experimental directions to be carried out in the future are suggested to explore the optimal solution to improve the treatment efficiency of CHCs in water.
在处理氯代烃（CHCs）污染方面，脱卤细菌仍然存在不足，例如代谢速率缓慢、底物范围有限、会形成有毒中间体。为了提高其脱氯能力，选择具有适当表面活性和生物相容性的生物炭及其复合材料进行耦合脱氯。由于其特殊的表面物理和化学性质，它促进了表面脱卤细菌形成生物膜，并改善了脱卤细菌的生存环境。其次，生物炭及其复合材料通过吸附、活化和催化为CHCs的去除提供了活性位点。这些位点可以是特定的金属中心、官能团或结构缺陷。在微生物介导下，这些位点可以经历活化和催化循环，从而提高脱氯效率。然而，目前对于基于生物炭的生物和非生物系统中脱氯机制缺乏系统的认识。因此，本文全面综述了生物炭及其复合材料作为CHCs降解的“万灵药”在吸附、催化、改善微生物群落结构以及促进CHCs降解和代谢方面的最新研究进展。还讨论了降解CHCs的去除效率、影响因素和反应机制。得出以下结论：在纯生物炭体系中，CHCs通过其表面化学键吸附固定在其表面；生物炭复合材料依靠持久性自由基和电子穿梭机制与CHCs反应，破坏其分子结构并使其还原；生物炭耦合微生物主要通过在生物和非生物生物体之间形成“电子穿梭桥”来还原CHCs。最后，提出了未来需要开展的实验方向，以探索提高水中CHCs处理效率的最佳解决方案。
