Regulating composition of Mn-CeOx nanoparticles with ultra-small sizes on Al2O3 for enhanced catalytic ozonation

Abstract

Herein, Al2O3 supported ultra-small Mn-CeOx nanoparticles (Mn-CeOx/Al2O3) are prepared by a facile impregnation method for removal of phenolic compounds via catalytic ozonation. Mn and Ce species are in the form of polyvalent oxide nanoparticles with an average size of 0.9 nm. The removal efficiency of total organic carbon for phenol-containing model wastewater by Mn-CeOx/Al2O3 shows a volcano relationship by changing the mass ratio of Mn and Ce, and reaches up to the peak value when the mass ratio is 5:5. The cycle stability tests suggest the removal efficiency of Mn-CeOx/Al2O3 could maintain at 90.16 % after 5 circles. The enhanced performance should be attributed to the optimized magnetism and accelerated charge transfer by composition regulation. The magnetic strength changing affects the adsorption mode of O3, while the redox cycle of Mn(IV)/Mn(III) and Ce(IV)/Ce(III) could enhance the activation of O3 to produce more ·OH and 1O2 for the organic molecules mineralization.