News of Batteries: Microbial fuel cell operating conditions, optimization of water

Microbial fuel cell operating conditions, optimization of water

Glucose as fuel, building a microbial fuel cell, were investigated by ion-exchange membrane type (and not), electrode material, electrode spacing, ionic strength (and add the potassium ferricyanide) on the performance of microbial fuel cells, the results show that : Using the homogeneous cation exchange membrane, not a polished high-purity graphite plate, electrode spacing 0.5 cm, adding NaCl solution and potassium ferricyanide to produce the maximum power density. Optimization of the microbial fuel cell operating conditions.

Microbial fuel cell is directly with the catalytic role of microbial fuel (such as organic acids, sugars, etc.) of the chemical energy is converted to electrical energy, domestic and industrial wastewater containing organic matter rich as its fuel source, from which direct access power. Microbial fuel cell performance of the main factors: microbial species, the chemical substrate, ion-exchange membrane type (or not), the battery internal resistance, ionic strength, electrode materials and electrode gap.

Microbial fuel cell (Microbial fuel cells, MFC) Yin and Yang are the two poles chamber volume 300 ml, the question at the poles to install a room in advance in 2% (y) NaCl solution, the ion exchange membrane immersed 24h (area 31 .3 cm2), ion-exchange membrane were placed on both sides of the anode and cathode, the anode chamber upper seal (leaving a sample port, doubles as a gas outlet), the cathode chamber is exposed to air. External circuit, an adjustable load resistor with a multimeter to measure the resistance and voltage values.

Take a brewery wastewater treatment sludge, wastewater in the laboratory glucose acclimation, the sludge obtained after the inoculation of domesticated 25m1, COD in the 5000 mg l-1 or so, lL glucose nutrient solution containing 4.699 , 0.489 ammonium chloride, potassium dihydrogen phosphate and other trace elements 0.119 (10 m1), adjust the pH value with sodium bicarbonate in about 7, and add 100 mm01.1-1 phosphate buffer solution. When the output voltage is low, the anode chamber in the centrifuge the solution, discard the supernatant (supernatant for the determination of COD, potassium dichromate method (GBll914-89)), add a new nutrient solution and phosphate buffer solution, Q intermittent operation, the battery fixed external resistance 500Q.

Respectively the homogeneous cation exchange membrane black, yellow-phase cation exchange membrane and the green phase anion-exchange membrane and not polished high purity graphite plate (7.4 cm 7.1 cm) for the electrodes. Of different ion-exchange membrane microbial fuel cell production of electricity (see Figure 1). It can be seen from Figure l, reaches a steady state, the use of homogeneous cation exchange membrane fuel cells produced by the microbial stability of the maximum power for 7.1 mw m ~, was followed by heterogeneous cation exchange membrane, 4.6 mW m ~, while the heterogeneous anion exchange membrane is only 3.5 mw m ~, which Kim and other "o use of anion exchange membranes have the maximum power density is not consistent with the conclusions, which may be the nature of the membrane used different about: used in the study of their anion exchange membrane is a chemical group NH,, with a NH, group of the anion exchange membrane to exchange of phosphate ions, thereby maintaining the pH value of the anode chamber 7, while the cation exchange membrane of the pH value of the anode chamber with the operation of the system will be gradually reduced, which will result in decreased activity of anaerobic sludge. In this experiment, we used anion exchange membrane, the chemical group is a CH: N ( CH,).. anion exchange membrane on the phosphate ion exchange capacity is relatively weak, and do not have the ability to exchange cations, which results not perform as cation exchange membrane.

Cation exchange membrane by phase, not polished high purity graphite plate (7.4 cm x7.1 cm) constructed microbial fuel cell to regulate the distance between electrodes were O. 5 cm and 10 cm, the corresponding production of electricity in Figure 4, Figure 4 shows the expansion of distance between electrodes makes the battery electric power production was significantly reduced (from 4.6 mw m. 2 dropped to 1.8 mw m ), which is due to the expansion of the electrode spacing makes the transfer of protons from the solution to expand, with a corresponding increase in resistance of microbial fuel cells, thereby reducing its electric power production.

Phase anion-exchange membrane using microbial fuel cell to run a cycle, the nutrient solution added 100 mm01.1. 1 of the NaCl solution, and then measured its production of electricity, the results shown in Figure 5. Add NaCl solution, the battery electric power production increased to a certain extent (from 3.5 mW m. 2 increased to 4.8 mw m. 2). Add a reference electrode with NaCl solution after measuring the voltage electrodes and found that the anode and the cathode voltage reduces the operating voltage increases, which makes the battery voltage increases, which is an increase of ionic strength, making the battery internal resistance decreases reasons.

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