Characterization of catalytic deactivation and regeneration processes in Mn-loaded zeolite catalysts for ozone oxidation of toluene

Catalytic oxidation of toluene by ozone at ambient temperature is a promising, energy-efficient method. However, challenges such as catalyst poisoning and deactivation remain significant obstacles. As such, understanding the deactivation mechanisms and the regeneration of catalysts is crucial for optimizing catalytic oxidation processes. This study investigates the deactivation and regeneration processes of Mn/MOR catalysts in the ozone-mediated oxidation of toluene. The highest toluene removal efficiency achieved was 92.3 % with a manganese loading of 1 wt. %, but after eight experimental cycles, the catalytic performance declined to 24.3 %. The deactivation of the catalyst was primarily attributed to the accumulation of by-products during toluene degradation, the loss of Mn³⁺, and the reduction in oxygen vacancies. Regeneration experiments demonstrated that exposure to hot air effectively oxidized intermediate products and restored the active sites, recovering 94.2 % of the initial catalytic performance. Additionally, the possible reaction pathway for toluene degradation was deduced through GC–MS analysis. This work demonstrates the possibility of recovery of this deactivated catalyst and provides ideas for whole-life catalyst management.