First researchers sustainable production...

First

Researchers sustainable production of hydrogen is a potential source of clean energy, using only water and bacteria. Now the problem, scientists say, is scaling up the process of providing large amounts of hydrogen for various purposes such as refueling vehicles or small generators. Hydrogen may be the ultimate clean fuel because burning Ityn a chemical reaction with oxygenyields only water vapor. Previously, researchers hydrogen production, but only when they complement energy produced by bacteria of electricity from external sourcessuch as obtained from renewable sources or fossil fuels strattera without prescritpion, says Bruce Logan, Environmental Engineer at Pennsylvania State University, University Park. In addition, by using devices that contain large areas of membrane that separates salt water from fresh, scientists tapped the potential difference that exists between them. These devices create only the potential difference, they do not generate electricity needed for hydrogen, Logan notes. Hydrogen atoms formed in such devices only when the flow of electrons in liquid, where they can be combined with hydrogen ions, and they, in turn, the atoms are connected with each other to create hydrogen. Now, Logan and Penn State Environmental Engineer Kim Younggy report this week

Materials of the National Academy of Sciences that they have something the other team: They have successfully combined two types of devices for generating hydrogen without external energy sources in general. The prototype device contains two small chambersone of bacteria and nutrients, the other holding salt water, where hydrogen producedthat divided into five stacked cells, through which researchers distributed fresh and salt water. Together, these composite cells occurs between 0. 5 and 0. 6 voltsenough, say researchers in order to produce hydrogen in microbial fuel cell in which bacteria feed on acetate compounds. For every 30 ml of sodium acetate is available for bacteria, the device is created between 21 and 26 ml of hydrogen during the day. Of course, this small amount, about four times the amount of fuel in disposable lighter, but it is enough to prove that hydrogen-generating concept works in the lab, the researchers say. Although the equipment needed to produce hydrogen is expensive, the device requires no external power energyand therefore greenhouse gases generated during the process. Device command "is simple, and their test results are well explained and unique," says Leonard Tender, a chemist from the U.S. Naval Research Laboratory in Washington, DC One of the problems in the way of expansion process, he says, will be the development of new materials for fuel components of membranes that are not easily clogged chemical by-products of bacteria that would reduce the flow of ions that help maintain the potential difference across the membrane. Once these obstacles intersect, however, the process offers the intriguing possibility of using organic substances in waste water for energy, he said. But Cesar Torres, chemical engineer at Arizona State University, Tempe, suggests that new technology is not quite ready for mass production of hydrogen. "This is a simple process, but chemistry and complex components," he says. "Technology necessary for the development and production of materials needed to produce effective, nonclogging membrane rapidly evolving, but there is still much research to do."

Another problem the expansion will "keep the bacteria happy," he says. Above all, he believes, will produce many, but not all the energy produced by bacteria. Trying to use all the energy produced by bacterial metabolism would not leave enough for microbes to grow, reproduce and evolve. .