Enhancement of Catalytic Activity of Cobalt Oxide for Catalytic Ozonation of Ammonium Ion in Water with Repeated Use

Catalytic activity of Co3O4 for oxidative decomposition of NH4+ with O-3 in water was greatly enhanced with each reuse of the catalyst under the reaction conditions while maintaining its high selectivity towards gaseous compounds. On the other hand, other metal oxide catalysts showed no or only a little enhancement of the activity. Formation of -NHx, groups on the surface of Co3O4 during the reaction caused the enhancement of the catalytic activity.