State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China.
State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China.
Water Res. 2022 Jun 30;218:118429. doi: 10.1016/j.watres.2022.118429. Epub 2022 Apr 9.
Electrode materials occupy most of the construction cost of the microbial electrochemical system (MES), and the low mechanical strength and poor electrochemical performance of the commonly used traditional carbon-based materials restrict the promotion and application of this technology. In this study, polymer-based three-dimensional (3D) honeycomb-structure (HS) materials with good mechanical properties were used as supporting materials. Graphene (GR), carbon nanotube (CNT), and polypyrrole (PPy) was separately chosen as a surface conductivity coating layer for preparing MES anodes. The introduction of GR, CNT, and PPy on HS increased surface roughness, hydrophilicity, O and N content, electrochemically active surface area, and decreased charge transfer internal resistance, which promoted the adhesion of microorganisms on their surface and enhanced the extracellular electron transfer process at the electrode/microbe interface. The CNT-HS anode system got the better maximal power density (1700.7 ± 149.0 mW/m) of the three modified anode systems and 3.60 times that of MES using CC (471.8 ± 27.2 mW/m) as the anode. The accelerated reactions of the redox species in the outer cell membrane, the promoted electron shuttle secretion, and the enhanced abundance of the tricarboxylic acid cycle-related functional genes in biofilm led to better performance of the CNT-HS anode system. The CNT-HS anode system also exhibited long-term operational stability (>6 months) and a good chemical oxygen demand degradation effect. Furthermore, CNT-HS material exhibited its cost advantage, and its projected cost is estimated to be about $1.8/m, much lower than the currently used MES anodes ($8.2-548.2/m). Considering the good mechanical properties, simple preparation process, low manufacturing cost, long-term stability, excellent bio-electrochemical performance, and good pollutant removal ability, HS-based anode has promising potential for high-performance MES in applications.
电极材料占据微生物电化学系统（MES）构建成本的大部分，而常用的传统碳基材料的机械强度低和电化学性能差限制了该技术的推广和应用。在本研究中，选用具有良好机械性能的聚合物基三维（3D）蜂窝状（HS）材料作为支撑材料。分别选择石墨烯（GR）、碳纳米管（CNT）和聚吡咯（PPy）作为表面导电性涂层，用于制备 MES 阳极。GR、CNT 和 PPy 在 HS 上的引入增加了表面粗糙度、亲水性、O 和 N 含量、电化学活性表面积，并降低了电荷转移内阻，这促进了微生物在其表面的附着，并增强了电极/微生物界面的细胞外电子转移过程。在三种改性阳极系统中，CNT-HS 阳极系统获得了更好的最大功率密度（1700.7±149.0 mW/m），是使用 CC（471.8±27.2 mW/m）作为阳极的 MES 的 3.60 倍。外细胞膜中氧化还原物质的加速反应、促进电子穿梭体的分泌以及生物膜中三羧酸循环相关功能基因的丰度增强，导致 CNT-HS 阳极系统的性能更好。CNT-HS 阳极系统还表现出长期运行稳定性（>6 个月）和良好的化学需氧量降解效果。此外，CNT-HS 材料表现出其成本优势，预计其成本约为 1.8 美元/m，远低于目前使用的 MES 阳极（8.2-548.2 美元/m）。考虑到良好的机械性能、简单的制备工艺、低制造成本、长期稳定性、优异的生物电化学性能和良好的污染物去除能力，基于 HS 的阳极在高性能 MES 的应用中具有广阔的应用前景。
