Wastewater Treatment using Activated Carbon Nanofiber Anode Microbial Fuel Cells (MFCs)

Microbial fuel cell (MFC) technology is a pioneering bio-electrochemical system (BES) exploiting anaerobic bacteria to harvest useful energy from various organic substrates in wastewater. Commercial anode's of significance for MFC applications are carbon based material (carbon cloth (CC), brush or graphite rod), which have been shown to have high internal resistance and low power generation capacities. The study investigated a new anode material, activated carbon nanofiber (ACNF) to enhance biofilm formation and electron transfer in the anode chamber of MFCs. The distinct features of ACNF are high porosity and exceptionally large surface areas, resulting in better biofilm growth, electron transfer, power generation and contaminant removal, which have a great potential for MFC systems to treat wastewaters. Batchscale tests showed that MFCs with ACNF and granular activated carbon (GAC) as anodes achieved power densities of 3.50±0.46W/m3 and 3.09±0.33W/m3 respectively, while SCMFCs with CC had a lower power density of 1.10±0.21W/m3. In addition, the MFCs with ACNF achieved higher contaminant removal efficiency (85±4%) than those of GAC (75±5%), and CC (70±3%). This work has revealed several distinct advantages of biofilm growth, electron transfer, power generation and organics removal for ACNF, with potential future applications of MFC systems to treat waste waters.