Selective wet air oxidation of diluted aqueous ammonia solutions over co-precipitated transition metal-aluminum catalysts

摘要

Catalytic wet air oxidation of ammonia over a co-precipitated transition metal-aluminum catalyst was investigated. Copper-aluminum (Cu-Al-O) catalyst exhibited the highest activity and N_2 selectivity among those prepared from Co, Fe, Mn, and Ni, 50% of 1500 ppm of ammonia could be removed from wastewater of pH 12 at 503 K under 2.0 MPa of air by using 4.0 g of analyst without formation of toxic nitrogen containing compounds. Cu and Al ions were not found in solution after the reaction. It has been found that the catalytic performance of Cu-Al-O catalyst was strongly dependent on the preparation methods. The co-precipitated Cu-Al-O catalysts showed high N_2 selectivity. The presence of CuO is concluded to promote the reaction and CuAl_2O_4 in bulk phase is needed to stabilize the catalyst.