Kinetics of the uptake of SO2 on mineral oxides: Improved initial uptake coefficients at 298 K from pulsed Knudsen cell experiments

Abstract

AbstractThe uptake of SO2 on γ‐Fe2O3, γ‐Al2O3, and Saharan dust has been studied at T = 298 K using a Knudsen cell reactor operated in a steady‐state as well as in a pulsed mode. The initial uptake coefficients determined in the steady‐state mode have been found to be affected by surface saturation as well as bulk diffusion of SO2 resulting in an apparent dependence of the initial uptake coefficients on the sample mass of the mineral oxides. However, by operating the Knudsen cell in the pulsed mode with shorter response time, these effects could be suppressed. Initial uptake coefficients of γini (Fe2O3) = (8.8 ± 0.4) × 10−2, γini (Al2O3) = (7.4 ± 0.9) × 10−3, and γini (Saharan dust) = (7.6 ± 0.5) × 10−2 were derived. This suggests that Fe2O3 is an important component in determining the reactivity of mineral dusts. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 242–249, 2006