Small boreholes embedded in the sediment layers make big difference in performance of sediment microbial fuel cells: Bioelectricity generation and microbial community

Autor: Kaiming Yang, Yu Xiang, Yan Wu, Zhiqin Li, Huiqin Luo, Fei Guo, Zongyang Shi
Rok vydání: 2021
Předmět:
Zdroj: International Journal of Hydrogen Energy. 46:30124-30134
ISSN: 0360-3199
DOI: 10.1016/j.ijhydene.2021.06.155
Popis: The practical applications of sediment microbial fuel cells (SMFCs) are limited by their low power densities. In this work, a novel SMFC configuration with a cylindrical borehole embedded in the sediment layer is proposed with expectations of reducing internal resistance, enhancing mass transfer, and accordingly increasing power density. Two types of boreholes with same diameter of 10 cm, but different depths of 3 cm and 6 cm are constructed in SMFCs (SMFC-3 and SMFC-6). Results demonstrate that SMFC-3 produces the highest maximum power density (65.6 mW/m2), which is 25.5% and 65.6% higher than that in SMFC-6 (52.3 mW/m2) and the control SMFC (SMFC-C, 39.4 mW/m2), respectively. The improved power performance in SMFC-3 is mainly due to the greatly reduced internal resistance. Compared to SMFC-6, the higher power density in SMFC-3 is also due to the relatively low overlying water pH values, providing suitable pH condition for cathodic reactions. Microbial community analyses demonstrate that Alphaproteobacteria and Gammaproteobacteria are major contributors to the bioelectricity, and that electroactive species enriched on the top and bottom sides of anodes are significantly different. Generally, embedding a small borehole into the sediment layer is an easy-to-implement and cost-effective strategy for improving the power performance of SMFCs.
Databáze: OpenAIRE