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Research Could Fuel Cars with Urine

While astronauts are recycling urine and sipping the results in plastic cups (or wine glasses, whatever they use up there), automobile owners may be powering cars with urine in the future. According to Dr. Gerardine Botte, an Associate Professor from the Chemical and Biomolecular Engineering department at Ohio University, extracting hydrogen from urine--using electrolysis--will cost less than extracting hydrogen from water.


To discover if the theory was indeed possible, Botte and her group of scientists formulated fake pee--or rather synthetic urine--for the initial tests. The idea is that the urea molecule incorporates four hydrogen atoms that are not quite as adhesive as they are with water molecules. Electrolysis easily oxidizes the urea molecule with an inexpensive nickel-based electrode using a voltage of 0.37V; 1.23V is needed to split water. However, Botte eventually received clearance to play around with real human pee although it's unknown whether the scientists donated personal samples, or received a batch from external sources.

"It took us some time to get clearance to work with human urine - which held up publication of the research," Botte told the Royal Society of Chemistry.

For now, it doesn't look as if the technology will be readily available anytime soon, as the method is "expensive and inefficient." The process of ridding the urea molecule actually sounds like an unpleasant experience, as urea naturally "hydrolyses" into ammonia before generating gas phase ammonia emissions. From there, the stink just gets worse, and could lead to asthma attacks, chronic bronchitis, and premature death.

Currently Botte and her group are conducting long term stability studies on their electrolysis systems as well as conducting "computational" experiments. One source of waste Botte plans to harvest is sewage plants. Upscaling the electrolysis technology wouldn't be the problem--she's afraid that there may be a lot of salt content.

One expert applauds Botte's attempt to find a more efficient way to obtain hydrogen without splitting water. Bruce Logan, an expert in energy generation from wastewater and director of Pennsylvania State University's H2E Center and Engineering Environmental Institute, not only cautioned that urea converts to ammonia by bacteria rather quickly, but believes that the earth's population should start shelving jars of pee, in the basement, or out in the barn.

"You have to remember about the P [phosphorus] in pee--globally we need to start thinking about conserving phosphorus for fertilizer, because, just like oil, one day the deposits are all going to run out and we need to start building phosphorus recycling into our infrastructure," he told the RSC.