PARTITIONING OF VOLATILE HALOCARBONS BETWEEN SURROGATES FOR ATMOSPHERIC SOLID AEROSOLS AND GAS PHASE AS EXAMINED BY TPD MS AND INVERSE GAS CHROMATOGRAPHY

The desorption non-isothermal kinetics of prelimina ry adsorbed Cl, Br, and I-containing volatile halocarbons from the surface of surrogates for atmosph eric solid aerosols (fumed silica and alumina, sili ca gel and H-mordenite) was studied by TPD MS. The TPD spe ctra demonstrate high heterogeneity of the surface studied. The average desorption activation energies and half-widths of the halocarbons desorption ener gy rectangular distribution were calculated. The relat ionships between the average desorption activation energies and molecular descriptors for the halocarbons were derived for the solids. The partitioning of th e halocarbons and additional volatile organics between su rrogates for mineral and carbonaceous atmospheric aerosols (silica gel, Carbopack S, Carbosil) was ex amined by using the inverse gas chromatography method. These data indicate to the energetic hetero geneity of the solid surfaces. The average adsorpti on energies and variances of the adsorption energy recta ngular distribution were calculated and connected w ith molecular descriptors of the volatiles. A relations hip is observed between average desorption activati on energies of halocarbons on the silica gel surface fro m TPD MS data and average adsorption energies in th ese systems determined using inverse gas chromatography method at finite concentrations.