碳还原光生物阴极微生物燃料电池中多能质传输及转化特性

Photo-biocathode microbial fuel cell (Photo-biocathode MFC) is a novel technology that can be used to degrade wastewater and simultaneously convert carbon dioxide to biofuel by using both bio-energy and light energy without extra power consumption. However, at present, the enhancement mechanism of multi-species transport as well as co-transformation of light energy and bio-energy on photo-biocathode MFC performance is not clear. In this project, we focus on a MFC with a photo-biocathode capable of reducing carbon dioxide to formic acid, and experimental investigates the synergetic enhancement mechanism of carbon dioxide reduction on photogenerated electron and cathodic biofilm. In addition, the effects of multi-phase flow characteristics in cathode, carbon dioxide concentration, light condition and conversion efficiency of photogenerated electron on the characteristics of reducing carbon dioxide to formic acid for the photo-biocathode and MFC performance will be investigated. Moreover, mathematic model describing multi-species transport characteristics in steady-state biofilm of anode will be developed. And then a theoretical model of the cathode, which is a coupling of the bioelectrochemical reaction, diffusion and convection of carbon dioxide as well as proton and photogenerated electron transfer, will be also established. Finally, a global model of multi-species transport that can comprehensively describe photo-biocathode MFC is expected to be developed. The relations of interaction among the bioelectrochemical reaction, multi- species transfer of anode and cathode, as well as the conversion characteristics of photogenerated electron will be revealed. This study will provide theoretical foundation for the research of photo-biocathode MFC.

光生物阴极微生物燃料电池在无外加电能时能同时实现废水的降解和二氧化碳向生物燃料的转化，是一种利用生物质能和光能的新技术。但目前该电池内多组分物质传输及光能和生物质能的协同转化对其性能强化机理尚未明确。本项目针对具有还原二氧化碳产甲酸的光生物阴极的微生物燃料电池，实验研究光生电子与阴极生物膜对二氧化碳还原的协同增强机理；阴极内多相流动特性、二氧化碳浓度、光照条件及阴极光生电子转化效率等因素对光生物阴极还原二氧化碳产甲酸特性及电池性能的影响；分别构建阳极侧稳态生物膜内多组分物质传输模型和阴极侧含生物电化学反应、二氧化碳扩散和对流、质子传输及光生电子传递耦合的理论模型，最终建立能够完整描写光生物阴极微生物燃料电池内多组分传输全局模型。本项目拟揭示电池内部阴阳极生物电化学反应、多组分传输以及阴极光生电子转化之间的相互作用关系，为光生物阴极微生物燃料电池的研究提供理论依据。

光生物阴极微生物燃料电池是一种利用生物质能和光能的新技术，在无外加电能时能同时实现废水的降解和CO2向燃料的转化。针对利用光能和生物能将废弃物（废气或废水）中的化学能转化为可用燃料的瓶颈问题，本项目通过研究生物阳极处理废水中电子传输特性及强化原理与方法，光阳极处理废气的光能和底物传输特性和氧化自由基的形成机制，强化阴极气体底物传输与转化机理，以及耦合系统中阴阳极电势匹配与性能的相互影响关系，达到强化废气或废水转化为CO2和高效还原为CO2为化学燃料的目的。主要研究成果如下：①开发了具有高效电子传输的开放式生物阳极，高光能利用和强甲醛气体吸附的转盘式光阳极，以及多自由基共存的协同降解光阳极体系，提高了阳极废气和废水的降解能力。②提出了增强气体底物扩散传输和转化的薄液膜式阴极，建立了气体扩散过程与薄液膜更新周期之间的数学模型，研究了底物扩散传输和光电反应特性与阴极性能的关系。③研究了阴阳极耦合系统中，阳极与阴极电势匹配特性与系统整体性能的关系。④利用CO2作为中间转化体，将阳极降解废气或废水产生的CO2自供给薄液膜式阴极，构建了同步提升阳极光生空穴-光生电子分离效率和阴极CO2还原为燃料速率的自循环CO2燃料电池体系，实现了废弃物高效彻底的向化工燃料转化。本项目研究结果有助于认识光生物阴极微生物燃料电池存在的多组分物质的传输特性和光生电化反应转化机制，促进有机废水处理和二氧化碳还原等处理技术的应用和发展。项目执行期间，发表SCI论文12篇（一区5篇、二区5篇、三区2篇，第一标注3篇，第二标注8篇，第三标注1篇），申请发明和新型实用专利6项，参加国内外相关学术会议4次，培养研究生4名、本科生16名。