Carbon nanotubes simultaneously as the anode and microbial carrier for up-flow fixed-bed microbial fuel cell

A novel up-flow fixed-bed microbial fuel cell (FBMFC) using carbon nanotubes (CNTs) as the anode and microbial carrier was developed for continuous treatment of wastewater and electricity generation. A maximal power density of 590mWm^-3 was achieved with a maximal chemical oxygen demand (COD) removal rate of 90% at an organic loading rate (OLR) of 3.94gCODl^-1d^-1. An OLR of up to 10.27gCODl^-1d^-1 caused the overloading of FBMFC, accompanied with an unexpected decrease in voltage generation below 0.1V and a sudden accumulation of volatile fatty acids (VFAs) up to 1.82gl^-1. The overloading also led to a rapid decline in COD removal rate (72%) and a morphology change of microbial consortia confirmed by scanning electron microscope (SEM). These results demonstrated the feasibility of Carbon nanotubes simultaneously as the anode and microbial carrier for up-flow fixed-bed microbial fuel cell. The overloading of MFC suggesting that further researches are still needed on improving the performance of FBMFC for energy production and wastewater treatment.