Study On The Effects And Mechanism Of Magnetic Field And Mixed Inoculation To Electricity Production Performance Of Microbial Fuel Cell

Microbial fuel cell (MFC) is a new technology for producing electricity directly from organics in wastewater using bacteria as catalyst. The paper mainly studied the effects and mechanism of dynamic treatment in vertical magnetic fields, application different strengths of magnetic field to anode, and inoculation with Geobacter sulfurreducens and Shewanella oneidensis MR-1 co-culture on electricity production. The main results were as follows:(1)Treatment with dynamic magnetic field prelonged the startup time, lowered the steady voltage, and increased the apparent internal resistance of reactors. The apparent internal resistance of the reactors with blank, 100mT,200mT magnetic field were 329Ω,507Ω and 353Ω respectively.The test results of electrochemical impedance spectroscopy indicated that the MFC with magnetic treatment had the higher charge transfer resistance compared to those without magnetic treatment. The charge transfer resistance of the reactors with blank, 100mT, 200mT magnetic field were 12.34Ω,28.29Ω and 16.87Ω respectively. The measurement of cyclic voltammetry found that the treatment with dynamic magnetic field reduced the electrochemical activity of exoelctrogens.(2)With the effect magnetic field, MFC get the higher power production than blank MFC. The polarization resistance of the reactors with magnetic field reduced obviously. With a certain intensity of magnetic field, the electroactive component on the electrode surface enhanced and the activation resistance was reduced. The concentration of electroactive component on the anode surface of the reactor with 100mT,200mT and 400mT MF was 4.58 × 10-10,9.01 × 10-10 and 7.36× 10-10 mol · cm-2 respectively, which was higher than that of blank reactor which was 3.60 × 10-10 mol · cm-2. The magnets were bound onto the external walls of anode chambers to obtain 200mT magnetic field intensities at the anode position and the power production of MFC which has started up was enhanced.(3)There is big impact of MFCs inoculated with different cells on the electricity production and impedance behavior. The production performance of MFC inoculated with co-culture bacteria was much better than the other two reactors inoculated with the sole bacteria. The co-culture MFC (0.039mW/m2) showed the best performance which enhanced 20% comparing with MFC inoculated with Geobacter sulfurreducens (0.032mW/m2), nearly 4 times to the MFC inoculated with Shewanella oneidensis_MR-1(0.0072mW/m2).