Selection Of Anode Materials And The Impact Of It On The Power Generation Of Single Chamber Microbial Fuel Cells

Microbial fuel cell (MFC) has been developed in recent years. It is a kind of bioelectrochemistry system which can obtain biological energy and treat wastewater at the same time. Single chamber microbial fuel cell has the advantage of access to higher power density. However, its coulomb efficiency is much lower and this shortcoming will be the most important restrictive factor for the developing. In this study, we would like to get higher power density and higher coulomb efficiency by trying several novel anode materials.In this article, we researched the impact of anode materials nickel-plated graphite conductive rubber, silver-plated glass conductive rubber, expanded graphite and tungsten carbide on the electricity generation of MFC. Among of the four materials , tungsten carbide packed MFC obtained the best results. Comparing electricity generation of tungsten carbide packed MFC with carbon fiber brush packed MFC, power density were 1077mW/m~2 and 1024mW/m~2, ohmic resistance were 11Ωand 16Ω, coulomb efficiency were 22.1% and18.3% respectively. The coulomb efficiency of tungsten carbide packed MFC was 15.8% higher than carbon fiber brush packed MFC. These show that anode material tungsten carbide can not only obtain higher power density, but also can get higher coulomb efficiency. Different filling patterns can impact the electricity generation of MFC. Among there particle sizes (0.85～2mm,2～4mm,4～6mm), 2~4mm particle tungsten carbide packed MFC obtained the best performance, the highest power density 848mW/m~2, the lowest internal resistance 120Ωand the lowest ohmic resistance 12.6Ω. MFC with the filling degree of 100% obtained power density 1088mW/m~2 and coulomb efficiency 23.4%. Both of these were much higher than 900mW/m~2 and 11.8% which were the performance of MFC with filling degree of 50%.Different materials composite pack in MFC impact the electricity generation. When carbon fiber brush composite packed with tungsten carbide, the much higher filling degree of tungsten carbide, the coulomb efficiency and the power density were much higher. The coulomb efficiency of MFC which was composite packed with expanded graphite and tungsten carbide was 2.84 times than only carbon fiber brush packed MFC. This is because that expanded graphite can absorb nonpolar molecular (oxygen) from polar molecular (water and acetate). And then it inhibits the oxygen's diffusion to the anode and decreases the substrate's consumption by aerobic microorganism. Futhermore, the coulomb efficiency was increased.