The Influences of Heterogeneous Reaction on Particle Optical Properties: A Laboratory Case of SO2 on Hematite and Hematite-NaCl Mixture

The particle optical property variation for heterogeneous reaction of SO
₂
on hematite and hematite-NaCl mixture was investigated in a static reaction chamber at 298 K using in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The increases of absorption and backward scattering coefficients are commonly higher in mixture with 50-70% NaCl than pure hematite and other mixtures. For both pure hematite and mixture, under reactions of 1-10% O
₂
concentrations, the absorption and backward scattering coefficients are in a higher increment than those of 20-30% O
₂
concentrations. The absorption and backward scattering coefficients rise by commonly larger magnitudes at high SO
₂
concentration than low SO
₂
concentration, in a quicker approach to equilibrium.