Synergistic mechanism of Ce-Mn in ZSM-5 carrier catalysts for catalytic oxidation of toluene

Abstract

Volatile organic compounds (VOCs) are the main components of air pollutants, posing threat to the public health and the environment. In this study, a series of CeMnOx-ZF catalysts with different metal loadings were prepared from coal fly ash (CFA), and the optimal activation route of CFA to the synthesize carrier and the toluene catalytic oxidation effects by carrier catalysts were investigated. The synergistic mechanism of Ce and Mn metals in CeMnOx-ZF catalysts were investigated. The results showed that, CFA exhibited the highest activity under the pretreatment conditions of the 15% HCl mass fraction, 1.5:1 alkali/ash ratio, and 500℃ calcination temperature. Under optimized reaction conditions (600 ppm initial toluene concentration, 30000 h−1 GHSV, and 120-390℃ reaction temperature), 20 wt.% CeMnOx-ZF catalyst exhibited an extremely high toluene removal efficiency with the maximum of 99.6%. After water vapor introduction, the toluene degradation efficiency remained at a stable level, but CO2 yield increased. After 100-hour cycle test, the 20 wt% CeMnOx-ZF catalyst still exhibited a high toluene degradation efficiency (96.5%), indicating its high stability. This study provides a simple and convenient method for CFA activation and proposes a feasible strategy for designing and synthesizing high-efficiency catalysts for the degradation of VOCs.