Total oxidation of isopropanol over manganese oxide modified ZSM-5 zeolite membrane catalysts

Abstract

Manganese oxide modified ZSM-5 membrane catalysts were prepared for the catalytic combustion of a volatile organic compound (isopropanol) over a zeolite membrane reactor. Characterization of all samples was carried out by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), N₂ adsorption/desorption, X-ray photoelectron spectroscopy (XPS) and H₂-temperature programmed reduction (H₂-TPR). The performance of the catalytic oxidation of a single VOC (isopropanol) was investigated over the zeolite membrane reactor based on Mn/ZSM-5/PSSF catalysts, the experimental results showed that the 0.5 M Mn/ZSM-5/PSSF-350 °C catalyst exhibited the best catalytic activity for isopropanol oxidation with 90% conversion of isopropanol at 222 °C with a feed concentration of 4.5 mg L⁻¹ and GHSV of 7643 h⁻¹, which was much lower than that of granular Mn/ZSM-5 catalyst (297 °C). The results of a reaction stability test revealed that the Mn/ZSM-5/PSSF catalysts possess excellent reaction stability for isopropanol oxidation for 50 h, and the conversion of isopropanol remained above 97% at 280 °C with a feed concentration of 4.5 mg L⁻¹ and GHSV of 7643 h⁻¹.