Heterogeneous and catalytic uptake of ozone on mineral oxides and dusts: A Knudsen cell investigation

Abstract

The uptake of ozone on various mineral powders has been studied using a Knudsen cell apparatus at T = 296 K. Samples included α-Al2O3, α-Fe2O3, SiO2, China loess and Saharan sand. Reactive uptake coefficients, γBET, were measured for the various particles and found to be 8 ± 5 × 10-5 for α-Al2O3, 1.8 ± 0.7 × 10-4 for α-Fe2O3 and 5 ± 3 × 10-5 for SiO2. The authentic dust samples were found to have γBET values of 2.7 ± 0.9 × 10-5 for China loess and 6 ± 3 × 10-5 for Saharan sand. Variations in the reactivity of the Saharan sand were observed as a function of sample treatment. Under the conditions of this study, heterogeneous uptake of ozone is catalytic and results in the destruction of ozone.