Integrated chamber-free microbial fuel cell for wastewater purification and bioenergy generation

An integrated chamber-free microbial fuel cell (iMFC) was constructed, which can be directly used for wastewater purification and energy recovery. The iMFC demonstrated potential electricity generating ability, producing 123.02 mW m −2 (688.90 mW m −3 ) with an open-circuit voltage of 0.75 V and current discharge of 294.32 mAh. Cyclic voltammetry analysis indicated that the electricity storage capacity contributed by pseudocapacitance effect enhanced power generation of iMFC. Electrochemical impedance analysis revealed a low internal resistance (60.20 Ω), mainly related to internal diffusion. In addition, iMFC had an excellent chemical oxygen demand (COD) removal capacity, removing 81.20% of wastewater COD in 48 h, with optimum coulombic efficiency of 23.07%. The high-throughput sequencing analysis (16S rRNA/16S rDNA) indicated that Comamonas , Delftia , and Flavobacterium were dominant on both anode and cathode with varying abundance. Additionally, Pseudomonas and Clostridium_sensu_stricto_13 contributed as important exoelectrogens. With concise architecture, the iMFC could be easily integrated and used in existing wastewater treatment plants without further construction, making it feasible for industrial application.