Synergistic catalytic wet oxidation of ammonia over carbon-supported low-loading Ru/Cu bimetallic catalyst

The manner of ammonia-containing wastewater in industrial production has always been an urgent issue that needs to be solved. Accordingly, a carbon-supported low-loading Ru/Cu bimetallic catalyst with high activity and hydrothermal stability was produced through facile disposal for catalytic wet air oxidation (CWAO). In the preparation process, Ru and Cu ions were loaded onto micro mesoporous carbon prepared through the calcination of potassium citrate by impregnation. Various characteristic techniques were utilized to characterize their structures and morphology, and results show that the calcination temperature with micro-mesopores' characteristics could regulate the morphology of carbon. The results of catalytic experiments demonstrated that the obtained catalyst showed excellent catalytic performance in the process of CWAO. The Ru/Cu@C-700 catalyst achieved 99.6 % conversion of ammonia water at 800 ppm and 99.1 % selectivity to nitrogen at 200 °C and 2 MPa O2 in 4 h. The ammonia nitrogen content in the treated water was less than 15 ppm, meeting the standard for direct discharge. Moreover, no apparent deactivation phenomenon was observed after five cycles, indicating that the prepared catalyst can effectively prevent the leaching of ruthenium and copper nanoparticles. The low loading (less than 1 %) of the Ru/Cu bimetallic catalyst can significantly reduce costs and can synergistically enhance conversion and selectivity, providing an effective strategy for studying the CWAO of ammonia.