Microbial fuel cell
(Trackback: http://www.best-laptop-battery.co.uk/blog )
Since the industrial revolution, has been plagued sewage treatment in developed and developing countries a major problem, because it expensive, is only of inputs, not outputs of the industry. And new microbial fuel cell can not only purify the water, but also for power generation, the emergence of its sewage treatment is expected to become a profitable industry. Although still in the continuous improvement of the product has not yet put into commercial production, but we have every reason to believe it has broad prospects for development.
Recently, by the United States Pennsylvania State University scientists, led by Logan, a research and development team announced that they have developed a new type of microbial fuel cell can be of untreated sewage into clean water and power.
Microbial fuel cell (MicrobiologicalFuelCells) there is not just a technology. As early as 1910, the British botanist Mark – the first bit of bacteria found in the culture medium to produce current, therefore, he made use of platinum electrodes, put it into E. coli and general yeast culture medium, the successful production of a the world’s first microbial fuel cell; in 1984, the United States to create a space for use in microbial fuel cell, which fuel for the astronauts of the urine and live bacteria, but it’s a very low discharge rate; In recent years, the use of Microbial generation of technology breakthroughs have emerged more, Pennsylvania State University environmental engineering professor Bruce – Logan is a new microbial fuel cell development team, he said, “the traditional is the use of hydrogen fuel cell power generation, but no one try to use organic-rich water to generate electricity. ”
A major innovation: a single slot design
Logan designed the battery and hydrogen fuel cell device to be somewhat similar, is a sealed cylindrical glass tank of resin, looks like a soda bottle. And hydrogen fuel cells, however different, the microbial fuel cell is a single reaction tank, containing eight graphite anode rod, and they stick around a cathode, confined to the middle slot between proton exchange membrane. Confined to the external tank of the closed circuit composed of copper, used for electronic flow path. When water was injected into reaction tank, the bacterial enzyme to break down organic matter in sewage, in the process of releasing electrons and protons. Among them, the electronic flow of the anode, and protons through the proton exchange membrane inside the flow of anode, where oxygen and air as well as the electronic generation of clean water combined. Thus completion of the sewage disposal. At the same time, the reaction bed is the electronic exchange between the cathode produced a voltage, so that the equipment can supply to the external circuit.
Reaction is a single slot design of microbial fuel cell innovation. Logan pointed out that most of the design of fuel cell response to the two groove-oriented – are the anode and cathode slot slot, slot in the anode in order to maintain anaerobic microbial growth; cathode tank should be maintained at aerobic conditions, electronic and oxygen combine with protons to form water molecules. And a single reaction tank in order to proton exchange membrane to link the two slot, and its function not only in aqueous solution can be divided into two slots, but also to avoid spread to another tank of oxygen. Electrobath trough of the two, other than the force required to provide dissolved oxygen to the cathode, and a single tank of fuel cell micro-organisms can be the way to continuous injection of air into the cathode, thereby reducing the cost of oxygen equipment.
Samples will be completed six months after
In generating capacity, according to Logan said, in the laboratory, the device can generate 72 kilowatts of current, you can drive a small fan. Although the current generated by small, but the equipment is much room for improvement. Invention from the report submitted to the present, Logan’s R & D team has the fuel cell power generation capacity to 350 watts, but Logan would like this value to achieve the ultimate 500-1000 watts. Such as maturity of the technology can be mass-produced microbial fuel cell power generation capacity will be greatly improved, and Logan believes that it can generate 500 kilowatts of the stability of current, about 300 family’s electricity consumption. Logan plans to build a large-scale microbial fuel cell sample, is expected to be completed six months later.
Application prospects
Although the device’s energy output is relatively low, but Logan said they are continually improving the technology, I believe that it can be used in small-scale sewage treatment factory. It is said that the device can also be used to deal with livestock waste water and waste plants, but also can be used in food-processing plants and even manned space inside.
Logan pointed out that as long as it is a place rich in organic matter can be the use of such batteries. However, the microbial fuel cell is the best use of sewage treatment, sewage treatment plant if the use of such equipment, so they can waste water treatment side of the side of power generation, and thus greatly reduce the cost of sewage treatment. Wastewater treatment plant to maintain the normal operation is a very high cost of things. Both developing countries and industrialized countries, wastewater treatment at the same time, the new generation fuel cell technology is very attractive. According to statistics of the U.S. National Development Committee, the United States need to address each of the 33 billion gallons of domestic sewage, the treatment cost about 25 billion U.S. dollars. Most of the cost of almost all spent on the maintenance of treatment plant operation of the energy required, so that if the microbial fuel cell can reduce costs and improve efficiency of electricity generation will be a huge savings for the wastewater treatment expenses.
For the majority of serious pollution of the developing countries, this technology is particularly useful because it can not only purify the water quality, disposal of refuse, while the power generated. Separate from the power this context, the Government has sufficient reason to retain the building and a sewage treatment plant. If the technology can promote the commercialization, waste or sewage treatment will be the country’s money-spinner rather than a heavy burden.
David – University of Toronto is a scientist, he estimated the energy potential in wastewater is 10 times the cost of processing. Logan believes that as long as they can use the potential power of 1 / 20, a sewage treatment plant can be resolved on the cost of sewage treatment.
Microbial fuel cell can also be used to deal with food-processing plants and farms, especially pig farms in the wastewater, in the past, to deal with these unpleasant stench of sewage expensive. NASA also is developing a similar technology, manned space flight in astronauts living in the garbage into energy.
New type of fuel cell materials have emerged
With the world’s fuel cell technology continues to develop, a new type of fuel cell materials continue to emerge, the world’s many well-known companies have also added to the fuel cell component of the study.
DuPont to develop and provide advanced materials for fuel cell components, including Nafion perfluorocarbon membrane and engineering polymers, used in proton exchange membrane (PEM) fuel cells. In 1980 the company began producing Nafion membrane, the current production capacity of 200,000 square meters. Nafion membrane electrolyzer placed as cathode barrier material, the use of hydrogen in the anode and cathode of the oxygen, after the completion of Nafion membrane electrochemical reaction, resulting in the release of ion-exchange effect of the electronics, electronic circuits to form an external current. Reaction process, the hydrogen ions through the Nafion membrane and oxygen ions into the water. DuPont’s Nafion membrane, and engineering materials have been applied to space flight. Now, more than 50% of the PEM fuel cell component materials provided by the DuPont Company.
Celanese Corporation and Honda Motor Company of Japan, to develop automotive fuel cell polymer membrane and the membrane electrode assembly (MEA). MEA by the solid polymer membrane and the catalytic electrode composition. Celanese Corporation successfully developed Polybenzimidazole high-temperature polymer membrane for MEA, its operating temperature can be as high as 180 ℃, and the traditional work of the fluorine resin film temperature of 100 ℃.
Ballard with Victrex company develops and manufactures PEM fuel cell using sulfonated polyether ketone polymer chain containing plasma, high-performance film is expected to reach production capacity of 50 tons / year, may be used to manufacture 100,000 membrane for automotive fuel cell use . Stanford Research Institute also developed for direct methanol fuel (DMFC) using polymer membrane for portable facilities. Motorola also with the Los Angeles National Laboratory to develop portable electronic facilities for DMFC membrane.
At present, the cost of fuel cell catalyst for the equivalent of 10 years ago 1 / 20, so as to fuel cells competitive with existing energy foundation. It is predicted that the end of this century, fuel cell industry is expected to reach sales of catalyst emissions from vehicles sales catalyst.
