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Biogas just became a cleaner option, thanks to a process developed at the
University of Reading. Plant and animal matter can be converted into a fuel
containing a mixture of hydrogen and methane. During the process, however, any
nitrogen in the biomass tends to end up as ammonia, which burns to form nitrogen
oxides—a cause of acid rain. Now Robert Burch and Barry Southward have
found a way to convert ammonia into water and nitrogen using a
12-tungstophosphoric acid catalyst. The technique could also prove useful for
cleaning up nitrogen oxide emissions from coal gas.