Botte's brainwave was to use urine instead of water. By weight, urine contains roughly 2 per cent urea, and each urea molecule contains four hydrogen atoms, which, crucially, are less tightly bound to the molecule than the hydrogen in water. Splitting these bonds would require less energy, making hydrogen production more efficient.Doing this would have two advantages. First, you can generate electricity. Second, it removes the urea from the environment. Urea is broken down to ammonia (NH3) which can cause environmental problems such as ecosystem acidification and eutrophication.
Last year, Botte's team reported that they had been able to generate hydrogen from urine using an electrolytic cell with cheap nickel-based electrodes running at only 0.37 volts- much less than the 1.23 volts it takes to split water (Chemical Communications, 2009, p 4859). Pure hydrogen bubbled off at the cathode, while nitrogen and carbon dioxide formed at the anode.
Tuesday, August 24, 2010
Using urine to power daily life.