Low Temperature Ammonia Oxidation Catalyst Studies

摘要

Many malodorous compounds are not only nuisance, but also a health threat under prolonged exposure. Ammonia (NH_3) is emitted from landfill and sewage treatment plant and associated with many agricultural activities (e.g. poultry and piggery). Ammonia is also a problem in public toilets, hospitals and nursing homes. Selective catalytic oxidation (SCO) can convert NH_3 to N_2 at mild temperature (i.e. 473-673 K) as shown in equation 1, however nitrous oxides (N_2O) and nitrogen oxides (NO_x) are often produced (cf. Eqn. 2 & 3). 4NH_3 + 5O_2 → 4NO + 6H_2O Eqn. 1 4NH_3 + 4O_2 → 2N_2O + 6H_2O Eqn. 2 4NH_3 + 3O_2 → 2N_2 + 6H_2O Eqn. 3 It has been reported that titanium supported vanadium catalyst is active for ammonia oxidation at temperatures above 523 K. Also, supported vanadium oxides are known to be efficient catalyst for the catalytic reduction of nitrogen oxides (NO_x) in the presence of ammonia. This work investigates the nanostructured vanadia/TiO_2 for low temperature catalytic remediation of ammonia in air.