Wet air oxidation of aqueous ammonia solution catalyzed by bimetallic Pt/Rh nanoparticle catalysts

Abstract

Ammonia (NH₃) plays a significant role in the chemical industry, and is widely used in industrial wastewater. In this study of bimetallic platinum‐rhodium nanoparticle catalysts, aqueous solutions containing 400–1,000 mg/L of ammonia were oxidized in a trickle‐bed reactor (TBR). Experimental results demonstrate that little ammonia was removed by wet oxidation in the absence of any catalyst, whereas around 99% of the ammonia was eliminated during wet oxidation over the bimetallic platinum‐rhodium nanoparticle catalyst at 503 K and an oxygen partial pressure of 2.0 MPa. There is a synergistic effect of the platinum‐rhodium bimetallic structure, which is the material with the highest ammonia reduction activity. Additionally, the effect of the initial concentration and reaction temperature on the removal of ammonia from the effluent streams was explored at a liquid hourly space velocity of under 9.0 h^–1 in wet catalytic processes.

Key words:

• ammonia
• nanoparticle catalysts
• trickle‐bed reactor
• wet oxidation