Microbial Fuel Cells And Electrochemical Studies On Mesoporous Zirconium Phosphate Anode Materials

Currently, sewage treatment technology is a process of exhausting a lot of electrical energy. Solving the energy consumption issue and reducing the anti-pollution cost are especially useful for the developing countries. Microbial fuel cell (MFC) can generate electricity while treating wastewater, so it attracts more attention as a new type of energy recovery technology. The major problems faced by MFC towards commercialization are the high internal resistance and the limitation in the structures designing to harvest more power.The biggest factor for energy output of battery is electron transfer in anode. In the current study, the modified microbial protein shell can make the electrode extend to the enzyme activity center. The distance of electron transfer is shortened greatly. With the development of nano science and technology, finding some nanomaterials have great potential in strengthening enzymes'stability and activation. Zirconium phosphate is gradually developed in recent years as a kind of multifunctional material. It has good biocompatibility, but the low conductivity limits zirconium phosphate's application as the anode in fuel cells.In this paper, we designed an air cathode MFC; Graphite felt and Pt/C were used for anode and cathode, respectively and oxygen in air was the final electron acceptor. Those designs had simplified the MFC devices and reduced internal resistance of battery. An open anode chamber reduced the operation cost. The energy output of MFC at different conditions was compared such as flow rate, concentration of glucose and so on. The results demonstrated that the best flow rate was 15.0 mL/min and optimal concentration of glucose was 1.0 g/L, while the great power output of battery was 90.2 mW/m2. The COD removal rate could reach 81.6 % for working 48 h.In chapter three of this paper, adjusting the volume of phosphoric acid could prepare the zirconium phosphate with different morphologies in hydrothermal synthesis. In the process, the surfactant was a template and phosphoric acid was the precipitation agent. Carbon was a hard template. Test results showed that when the amount of phosphate was more than 2.4 mol/L, we could make zirconium phosphate to be hexagon nano piece with the size of 200 nm~300 nm and thickness of 5 nm~ 10 nm. When the amount of phosphate was 1.2 mol/L, zirconium phosphate was mesoporous structure materials with bore of 3 nm. Using XC-72 as a template ZrP/XC-72 complex was synthesized. Their abilities of immobilizing GOD were compared. The Ks were 1.3 s-1,1.6 s-1,2.0 s-1 for platelike ZrP, mesoporous ZrP and ZrP/XC-72 respectively. That was the electronic transfer rate of zirconium phosphate with mesoporous structure was faster than platelike zirconium phosphate and ZrP/XC-72 could improve the electronic transfer rate of an electrode. The amount of enzyme loading on the surface of electrode was 1.4×10-10 mol/cm2, 6.6×10-11 mol/cm2 and 1.8×10-10 mol/cm2 respectively. Those were 1~2 orders of magnitude better than that reported in the literature.