Selective wet-air oxidation of diluted aqueous ammonia solutions over supported Ni catalysts.

Wet-air oxidation (WAO) of diluted aqueous ammonia solutions over Ni supported on Al(2)O(3) catalysts was investigated. A nitrogen selectivity of approximately 90% was achieved by the WAO of ammonia over the 20-wt% Ni/Al(2)O(3) catalyst at 503K, a reaction time of 2h and air-feed pressure of 2.0MPa without the dissolution of Ni during the reaction. Ni/Al(2)O(3) pretreated by calcinations in air at 1173K for 4h showed high stability due to the formation of a NiAl(2)O(4) phase.