Development of Hybrid Microbial Fuel Cell for Improved Power Generation under Solar Irradiation

Abstract

Fossil fuels are running out because of human activities, and consumption of fossil fuels increases concentration of carbon dioxide that causes global warming. Therefore, developing a new renewable energy is needed. Microbial fuel cells (MFCs) are eco-friendly technology that can treat wastewater and generate bioelectricity at the same time. But there are some limitations such as low power output and expensive material cost. Thus, this study was conducted to overcome low efficiency of MFCs by developing a new solar hybrid system and current collector that can reduce internal resistance of MFCs. First, suitable photoactive material must be used to harvest sunlight. In this study, N-doped TiO2 nanotubes were used as photoanodes because of their photostability, high electron transfer ability and broad absorption range. Additional electrons are generated from photoanode by light irradiation and it increased power output around 34.9 % compared with a normal MFC reactor. Second, the effect of current collectors was investigated. Current collector must have corrosion resistance in the aqueous solution. Therefore, titanium and stainless steel were used. Graphene oxide is coated on the current collector surface because of its excellent mobility of charge carriers, a large specific surface and good mechanical stability. The highest voltage was generated from the reactor which nanostructured stainless steel 304 mesh was used (452 mV). ⓒ 2015 DGIST