| Microbial Fuel cells (MFC) is a kind of Fuel cells, through microbial metabolismoxidizing organic matter and generating electricity device, using microorganism asanode catalyst, which has a wide range of raw materials, mild reaction conditions, highefficiency of energy utilization etc. But at present there are still problems, themechanism of electricity generation is fuzzy, the characteristics of electricigens produceelectrical is not clear, the control parameter is not reasonable. The electricigens wasused as the core of MFC output voltage. It has important theoretical and practicalsignificance for understanding the mechanism of electricity generation and optimizationof MFC control parameter by analysis its biological characteristics.Based on the carbon cloth as the anode, carbon paper with platinum as cathode,constitute "two-in-one" single chamber microbial fuel cells. The return sludge fromXi’an fourth sewage treatment plant make as inoculation sludge and artificialwastewater act as electricity generation. Study MFC startup characteristics and the MFCproduced electrical properties and electrochemical activity after controlling andchanging the anode potential, oxidation reduction potential. In order to analysismechanism of electricity production, analyze the electrogenesis bacteria metabolic type,look for the best control operation parameters, improve the MFC output voltage.The results show that:(1) In the moment of MFC starting, by changing the influent substrate ORP valueand researching MFC instantaneous output voltage size and the corresponding time, theresults showed that the water matrix with higher ORP is not conducive to the output ofthe MFC instantaneous voltage, that the higher influent substrate ORP is, the more time MFC output voltage need to achieve the same output voltage.(2) On the basis of the previous design test to increase the step of sonication, Whenthe output voltage is150mV Hanging membrane successful anode carbon cloth sonicateinto the the pure matrix and containing suspended microorganisms matrix, then gettingthe output voltage of4.6mV and15.5mV. the conclusion show that Electricityproduction microbial has no effect on anode carbon cloth in the adhesion process, thatMFC output voltage mainly rely on the anode attachment microorganisms andsuspended microbial contribute to the output voltage.(3) In the normal start, the anode potential by-380mV were reduced to-700mVand increased to200mV process, coulombic efficiency were increased from3%to6.7%and19.7%; the maximum power density from37.48mW/m2were reduced to8.56mW/m2and increases to65.4mW/m2; and the resistance (except200mV reduced to372Ω) generally increased; fermentation types to propionic acid type fermentation easydecomposition, organic acids can rapidly decompose at in20h. Show that, when theanode potential is about-200mV, MFC can get coulombic high efficiency, the biggestmaximum power density, reduce the transfer impedance and impedance allows MFC tostable operation without reducing the rate of reaction condition.(4) In normal startup, when MFC elevated the ORP from-250mV to-100mVprocess, coulombic efficiency from3%to5.2%in the first and then decreased to3.9%;maximum power density is also reduced by the37.48mW/m2to8.56mW/m2; resistanceincreased from599Ω to1490Ω. Show that, MFC redox potential increased, coulombicefficiency, maximum power density decreased, the resistance increased, because ofcontinuing leads to oxygen. This may be due to inhibition of anaerobic fermentation, thereaction rate is reduced, and the charge transfer resistance and increase the electrode/solution interface due to the electrical double layer capacitor. |
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