Insight into the performance discrepancy of GAC and CAC as air-cathode materials in constructed wetland-microbial fuel cell system

• DOI: 10.1016/j.scitotenv.2021.152078
• Publication Date: 2021-12-01T07:34:20Z
• Authors: Bin Ji; Yaqian Zhao; Yang Yang; Cheng Tang; Yunyu Dai; Xiaomeng Zhang; Yiping Tai; Ran Tao; Weifeng Ruan
• Keywords: Electricity; Bioelectric Energy Sources; Charcoal; Wetlands; 0211 other engineering and technologies; 02 engineering and technology; Wastewater; Electrodes; 7. Clean energy; 6. Clean water

Constructed wetland-microbial fuel cell (CW-MFC) has exhibited the performance discrepancy between using granular activated carbon (GAC) and columnar activated carbon (CAC) as air-cathode materials. No doubt, this is linked with electrochemical performance and decontaminants characteristics in the CW-MFC system. To provide insight into this performance discrepancy, three CW-MFCs were designed with different carbon-material to construct varied shapes of air-cathodes. The results showed that the ring-shaped cathode filled with GAC yielded a highest voltage of 458 mV with maximum power density of 13.71 mW m-2 and >90% COD removal in the CW-MFC system. The electrochemical characteristics and the electron transport system activity (ETSA) are the driven force to bring the GAC a better electron transportation and oxygen reduction reaction (ORR). This will help elucidating underlying mechanisms of different activated carbon for air-cathode and thus promote its large application.