Abatement of toluene from polluted air over Mn/Clinoptilolite–CeO2 nanopowder: Impregnation vs. ultrasound assisted synthesis with various Mn-loading

Abstract

Total oxidation of toluene over Mn(5%, 10%, 15%)/Clinoptilolite–CeO2 nanocatalysts was performed. Mn was doped via two different methods of impregnation and sonochemistry. The catalysts were characterized by XRD, FESEM, EDX, BET and FTIR analyses. The physicochemical characterizations showed superior properties of sonochemically synthesised nanocatalysts like homogenous morphology, small and dispersed particles, and strong interaction. Addition of CeO2 as a promoter to acid-treated clinoptilolite remarkably increased catalytic activity. XRD analysis demonstrated acid treatment of clinoptilolite induces noticeable decrease in crystals size and their crystallinity, while the specific surface area increased. Furthermore, no obvious peaks related to MnOx were found in XRD patterns even at high loadings of Mn which might be attributed to the high dispersion of particles in sonochemistry method. Due to the effect of sonication power, even at high loadings of Mn(15%), the morphology of the catalyst was agglomeration free and surface area was high. Comparison of catalytic activity of sonochemically and impregnated Mn(5%)/Clinoptilolite–CeO2 nanocatalyst showed that sonochemically synthesized catalyst can oxidize toluene 5–10% more than impregnated one at all temperature ranges. Increasing metal content enhanced the catalytic activity.