| Microbial fuel cell(MFC) is adevice directly converting microbial metabolic energy into electricity with the microbial catalysts, the development of MFC in the fields of environmental Protection and biomass energy will be greatlyattraetive The study was designed to two kinds of MFC devices, named intermittent flow and continuous flow, a carbon rod is used as the anode material, while a piece of carbon paper is used as the cathode material. The bacteria came from the sludge of an anaerobic process of a white wine distillery in Xuzhou, the inoculum concentration about 300 m L in intermittent flow and about 1000 m L in continuous flow were needed. First, under the condition of intermittent streams, different DC voltage electrically induced the sludge, using sodium acetate that has the concentration of 1000 mg / L as carbon source. After 7 days of culture, the intermittent flow experiment entered into electricity production stage, choosing the best DC voltage. Then under the continuous flow condition, respectively, using anaerobic sludge started to run the MFC, and the sludge domesticated with the best DC voltage in the intermittent flow experiment.In the intermittent stream running, pulsing ± 1.5V DC voltage, the output voltage of the system is extremely weak, indicating that a high voltage can inhibit the growth of microorganisms. Negative voltage produced far less electric power than positive voltage in each group, indicating that DC voltage could hinder the production of electricity when the electrons transfer in the opposite direction of the electrons in the electricity production process, causing voltage losses. The 1.0V DC voltage is the optimal voltage, compared to the electrical stimulation of 0.5V, its electrical induction effect is more obvious, having more superior electrical properties, indicating that the microorganism is capable of withstand voltage stimulus of low intensity range, the larger the intensity of electrical stimulation, more conducive to the growth and increasing its electricity generation cellular activity of microorganisms.In the continuous flow operation, first, used the optimum voltage to induced the anaerobic sludge, during the time, did a test of producing electricity for a short period about 1.5h at the same time on each day, finding that bacteria produced more and more electricity every day. The electricity production capacity had gradually reached the maximum of 1.82 V in the first 10 days, exceeding the rated voltage of the power supply. These showed that under the optimum voltage stimulation, produce electricity capacity of bacteria had been improved.The stable voltage value of the MFC which operated directly had reached 241 m V, spent 25 days, while the MFC domesticated with the 1.0V DC generated a stable voltage value of 258 m V, about 7% higher than the former, a successful start time is 17 days, comparing with the former, it reduced by 32%. After reaching a stable electricity-producing situation, changed the resistance value, to get the corresponding voltage, drew a polarization curve and a power density curve, estimating that the internal resistance of unpowered and power-train MFC were 580.7Ω and 636.7Ω, 486.1Ω and 557.8Ω. The maximum power density of 20.92 m W/ m and 24.452 m W/ m. Under different concentrations of organic matter and HRT, Investigated the effects of electrically induced acclimation on electricity-producing properties of bacteria,found in the lower concentration range, the greater the concentration of organic matter, the higher the voltage output. When HRT is less than 4h, in the MFC system, shorter time is more conducive to the growth of electricity-producing bacteria.This study confirmed that domesticating microbes by DC voltage could improve their electricity-producing capacity and identified the most suitable electrically induced voltage, studied the favorable operating environment for electrical power producing bacteria after acclimation. And provides a reference for the later practical application. |
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