Application of Mn-based active carbon foam in toluene treatment and study on its microwave regeneration performance

Abstract

The development of efficient and regenerable non-noble metal catalysts is crucial for the removal of volatile organic compounds (VOCs). In this study, a manganese oxide-loaded activated coal-based foam carbon (MnO_x@ACF) catalyst was synthesized from coal for the catalytic oxidation of toluene. The optimized catalyst, with 8 wt% Mn loading and calcined at 500 °C, achieved a toluene conversion of 88% at 400 °C, outperforming many reported analogues. This high activity is attributed to its mesoporous structure, abundant Mn³⁺/Mn⁴⁺ species, and active lattice oxygen. Furthermore, microwave irradiation was successfully employed to regenerate the spent catalyst. Under optimal conditions (800 W, 600 °C, 15 min), the process effectively restored the material's adsorption capacity and recovered 81.8% of its initial catalytic activity. This work not only presents a high-value utilization pathway for coal but also highlights the potential of microwave regeneration for sustainable environmental catalysis, despite noting a gradual decline in performance over multiple regeneration cycles.