Raman spectroscopy studies of reactions between sulfur dioxide and microparticles of hydroxides

Gas-aerosol chemical reactions between dilute SO2 and alkali-metal hydroxides have been explored using elastic and inelastic (Raman) light scattering. Single charged particles of NaOH, KOH, and Ca(OH)(2) were levitated electrodynamically in a reaction chamber and exposed to humid nitrogen. Particles that were not water soluble remained crystalline while water soluble compounds deliquesced into solution microdroplets. The resulting solids or solutions were reacted with dilute SO2 in humid N-2. Elastic scattering measurements and Raman spectra were taken during the gas-aerosol reactions, and results indicate that reaction products and sorbent utilization are highly dependent on the water content of the particle.