Constructing and operating of mediator- and membrane-less microbial fuel cell

In the microbial fuel cell, the microbial is used as anodic catalyst and the chemical energy is directly changed into electrical energy. In this paper, a mediator- and membrane-less microbial fuel cell was constructed, in which the domestic wastewater was used as inoculant and glucose as fuel. The effects of glucose concentration, oxygen and phenol addition, operating temperature and outer resistance on the cell performance were investigated, besides, the kinetic characteristic of the microbial and tile inner resistance of the cell were analyzed. The results show that it is the microbial adsorbed on the anode, not the one existed in the solution, that transfer the electrons to the anode, and in the range of low substrate concentration (-1), the relation of outer voltage and glucose concentration agrees with Monod equation. Oxygen is adverse to current output because of electron transferring to oxygen during aerobic metabolism, and after long domestication, the microbial in cell can adapt well to phenol, but phenol is little responsible for the current output of the cell. It was found that the optimal temperature for microbial in cell is about 35°C, and the relation between the outer voltage and current output is linear, it can be expressed as: V = 525-418i with correlation coefficient r = 0.998, accordingly, the inner resistance of the cell is 418Ω. The power density of the cell arrives its maximum when outer resistance is about 500Ω, which is close to the inner resistance of the cell.