Study on the Refractory and Toxic Wastewater with Microbial Fuel Cell
|School||Harbin Engineering University|
|Keywords||microbial fuel cell p-nitrophenol methylene blue Cr(VI) (the hexavalent chrome) the wastewater treatment|
Microbial fuel cell (MFC), as a new kind of wastewater treatment technology, can generate electricity energy while treating wastewater. A single MFC and a double-chamber MFC were constructed in this paper, the effects of wastewater degradation and the batter performance at different exotic materials in the wastewater were studied.To remove the p-nitrophenol, this paper used the single-chamber MFC with the air cathode and the carbon felt anode, the battery properties and the organic removal effects under the mixture of different p-nitrophenol concentrations and glucose solution were investigated. The results showed that electricity can be generated by the MFC with the mixture of the different p-nitrophenol concentrations (0 mg·L-1,25 mg·L-1,50 mg·L-1,100 mg·L-1 and 250 mg·L-1) and 500 mg·L-1 glucose solution. With the increasing concentration of p-nitrophenol, open-circuit voltage, cathode and anode, the quantity of electricity, coulomb efficiency, COD removal rate and the removal rate of p-nitrophenol are accordingly reduced.In the glucose concentration of 500 mg·L-1 and the p-nitrophenol concentration of 100 mg·L-1 below, the removal rate of p-nitrophenol and COD removal rate were both over 94%, and the degradation process is also consistent with the first-order reaction kinetics, R2 is above 0.9775. Therefore it is feasible using the microbial fuel cell to treat the mixed wastewater of glucose and p-nitrophenol and to generate electricity, the technology can provide a new way of treating wastewater with p-nitrophenol.The paper also investigated the color-removing effects of the methylene blue dye wastewater with the single-chamber microbial fuel cell, and studied the performance of the MFC and the removal effects of methylene blue under different concentrations of the methylene blue dye. The results showed that the mixture of different methylene concentrations (0 mg·L-1,25 mg·L-1,50 mg·L-1, 100 mg·L-1 and 250 mg·L-1) and 500 mg·L-1 glucose solution can generate electricity. In this experiment, the hydraulic retention time lasted four days and the removal rate of the methylene blue and COD were more than 90%. When the methylene blue was used as a single substrate, the removal rate is only 76%, less than the treatment effect with the mixture. Using MFC to treat the mixture wastewater of glucose and methylene blue, the effects would get better and can generate the electricity simultaneously. This provides a new method of treating wastewater with methylene.The paper constructed a double-chamber microbial fuel cell with the carbon felt as the anode and the graphite plate as the cathode, and examined the removal effects of hexavalent chromium and the effects on the performance of generating electricity of the battery when the hexavalent chromium is taken as the battery cathode electron acceptor. The results showed that with the decreasing of the cathode solution pH value, the removal of hexavalent chromium got better. The removal rate (the time of the hydraulic retention time is ten hours) went up to 99.94%(pH=2) from 22.34%(pH=6), the open circuit voltage increased from 285mV (pH=6) to 603mV (pH=2), the output power of the battery increased from 235.63 mW·m-3 (pH=6) to 1334.82mW·m-3 (pH=2), and the increasing catholyte of the initial hexavalent chrome concentration was helpful to improve the open circuit voltage and to reduce the internal resistance, thus raise the output power of the battery from 332.85 mW·m-3 to 4580.36 mW·m-3. However, the removal effects of the hexavalent chrome went bad. It is a feasible technology using the MFC to treating the wastewater with Cr (Ⅵ) while generating electricity. MFC technology is characterized as cheap operation cost, satisfied treatment effects, the little chromium residue, and Cr(Ⅵ)-proof load high, especially generating the electricity simultaneously. All of this provides a new method of treating the wastewater with the chromium.The results show that the microbial fuel cell can not only degrade the wastewater with the toxic materials but also generate the electricity at the same time, and can get better treatment effects and electricity-producing performance. This provides the evidence for the feasible technology using the microbial fuel cell to treat the wastewater with the toxic materials and expand its application to the field of the wastewater treatment.