提高微生物电解池固定CO2合成CH4的效能研究和机理解析

温室气体CO2已成为全世界关注的焦点，CO2的固定及资源化利用受到广泛重视。近年来微生物电解池（MECs）固定CO2合成碳氢化合物已成为研究热点。现阶段生物电合成双碳及以上化合物还存在产率低、产物难分离的缺陷，而通过MECs固定CO2合成CH4是一项具有应用潜力的技术。目前，CH4合成外加电压较高（-0.7~-1.2（vs. Ag/AgCl）），并有副产物乙酸的产生。为提高MECs合成CH4的效能，本项目首次以氮掺杂碳纳米管（NCNTs）修饰碳布构建复合阴极，降低CO2还原过电势；在此基础上，构建双阴极MECs系统，增加CO2传质空间；同时富集乙酸型产甲烷菌，避免乙酸积累。通过对微生物群落结构、甲烷合成路径和电子转移机制等方面的研究揭示MECs合成甲烷的机理。最后将MECs 与MFCs偶联原位处理生活污水并还原有机物降解释放的CO2合成CH4，为生物电合成实现CO2的循环利用提供技术支撑。

Conversion of carbon dioxide (CO2) to valuable hydrocarbon are located at the forefront of CO2 reduction research. Rapidly developing microbial electrolysis cells (MECs) are part of a diverse platform of sustainable CO2 ultilization process. As far as we are aware, the production of multicarbon oganisms is lower and hard to be separated. Therefore, it is believed that conversion of CO2 into CH4 by MECs is a promising technology. However, set potential (> -0.7 V (vs Ag/AgCl)) as well as byproduct actate making against CH4 production. In order to enhance production of CH4 from MECs, it is first time to use nitrogen-drop carbon nanotubes（NCNTs）modified carbon cloth composite cathodic materials to reduce the overpotential. Moreover, doubling the gas diffusion area by adding an additional air cathode to provide a suitable biofilm microenvironment to preferentially retain a higher abundance of the slow-growing Methanogens. Meanwhile, pre-enriched acetophilic methanogenic culture will be added into reactors to avoid accumulation of actate. Also, mechanisms for CH4 production by MECs will be explored from microorganisms, pathways and electron transfer. Furthermore, an MECs-MFCs coupled system for CH4 poduction from waste water will be developed.