Electricity generation in microbial fuel cell from wet torrefaction wastewater and locally developed corncob electrodes

Corncob pyrochar activated with steam (CCA) and nonactivated corncob pyrochar (NCC) were produced and characterized. The performance of the best material was tested in a dual-chambered microbial fuel cell (MFC) as an electrode for bioelectricity generation using wet torrefaction wastewater as substrate. Pyrolysis of 80.3 g of dried corncobs was carried out at 600 degrees C under a constant N-2 flow of 3 L min(-1) for 30 min and the resulting pyrochar was activated using steam also at 600 degrees C. Voltage and current outputs from the MFC were recorded daily for 18 days. The proximate and Brunauer-Emmett-Teller (BET) surface area analyses revealed that CCA had the highest fixed carbon content of 71.9 % and higher surface area of 104.0 m(2) g(-1) respectively. A larger pore diameter of 1.9 x 10(-3) mu m was also recorded with the CCA than 1.2 x 10(-3) mu m for NCC. The MFC produced a maximum power output of 21.5 mW. The physicochemical analyses of the wastewater effluent revealed an increased electrical conductivity from 1724 to 3460 mu S cm(-1) with a significant decrease by 91.9% in the total organic carbon (TOC) from 3700 to 298 mg L-1. Steam activation increases the surface area, porosity, stability and redox reversibility of the corncob pyrochar. Therefore, steam-activated corncob pyrochar performed well in MFCs due to the high power output observed.

Automated summary

Steam activation of corncob pyrochar increases surface area, porosity, stability, and redox reversibility, leading to high power output in microbial fuel cells.