Catalytic Wet Oxidation of Ammonia Solution: Activity of the Cu-La-Ce/Cordierite Composite Catalyst

Aqueous solutions that contained 200 to 1000 mg/L of ammonia were oxidized in a trickle-bed reactor (TBR) in this study of Cu-La-Ce/cordierite composite catalysts, which were prepared by the co-precipitation of copper nitrate, lanthanum nitrate and cerium nitrate at various weight ratios coated on cordierite substances. Results demonstrated that the conversion of ammonia by wet oxidation in the presence of Cu-La-Ce/cordierite composite catalysts was a function of the metal loading weight ratio of the catalyst. Ammonia solutions were barely removed by wet oxidation in the absence of any catalyst, while around 91% of the ammonia was reduced during the wet oxidation over the Cu-La-Ce/cordierite composite catalyst at 473 K and an oxygen partial pressure of 3.0 MPa. Furthermore, the effect of the initial concentration and reaction temperature on the removal of ammonia from the effluent streams was also investigated at a liquid hourly space velocity of under 5.4 hr⁻¹ in wet catalytic processes.