Remediation of various naturally oxygenated volatile organic compounds (O-VOCS) by Mn- and Cr-supported γ-Al2O3 nanocatalysts

Abstract

The catalytic combustions of different naturally oxygenated volatile organic compounds (ethyl acetate, isopropanol, methyl ethyl ketone (MEK), and benzyl alcohol) alone and in binary mixtures were investigated over pure γ-Al2 O3, Mn/γ-Al2 O3, and Cr/γ-Al2 O3. The catalysts were prepared by the wet impregnation method and were characterized using XRD, ICP-AES, SEM, and BET. Mn/γ-Al2 O3 showed higher activity than others in combustion of the O-VOCs, whereas complete conversion of isopropanol (the most reactive O-VOC) occurred at 350 °C and 400 °C on Mn/γ-Al 2 O3 and Cr/γ-Al2 O3, respectively. The following order was found for reactivity of organic compounds in single form: isopropanol > benzyl alcohol > ethyl acetate > MEK. There was no relation between activity of the catalyst and BET surface area. An inhibition/promotion effect was found in the oxidation of O-VOC binary mixtures because of the competitive adsorption on the catalyst, leading to an oxidation behavior for O-VOC binary mixtures different than that of single components. The presence of water vapor as a co-feed had an inhibition effect on isopropanol oxidation and was temperature-dependent such that it decreased above 350 °C.