Study of gas phase reactions, aerosol formation and growth dynamics of toxic metals at high temperatures

Fine particles can significantly affect human health; meanwhile, ultrafine particles are finding use in several technological applications. Different aspects that affect the formation of fine particles at high temperature environments were studied in this work.; Condensation characteristic times for systems of simultaneous particle growth and vapor consumption were developed. Several illustrations of these expressions were shown by applications in designing systems using condensation as the primary growth mechanisms and in estimating the importance of condensation in aerosol systems by comparing the various characteristic times.; The discrete-sectional model is an important tool to study aerosol dynamics. Numerical diffusion, which was inherent in the model, was investigated in this work. The errors are found due to: (1) the deviations of the derived aerosol properties in sectional formulation, and (2) the interchange between discrete-size and sectional aerosols. Parametric studies were conducted to evaluate the effects of model parameters (section spacing, conserved aerosol property and number of discrete sizes).; Experiments were conducted for lead species aerosols to develop better insights into the formation and growth in multicomponent environments. The effect of chlorine on lead species systems was studied by varying the Cl/Pb ratio. Various species were identified in the intermediate ratios indicating the importance of reaction pathways and multicomponent nucleation. Condensation was shown to be the primary growth mechanism. Nucleation theories using bulk properties were found inappropriate for metallic species.; Aerosol processes were also used to in-situ generate titania particles, with in-situ UV radiation, for better capture of vapor phase elemental mercury. The in-situ generated particles were found better than the bulk particles due to the nanosized agglomerated primary particles produced in such processes which had better exposure to UV radiation and higher surface area for mercury adsorption. As mercury oxide was with titania agglomerates, it can be collected using typical control devices downstream.; To better predict the nucleation rates of metallic species, Monte Carlo methods were applied to determine the Gibbs free energies of formation of mercury clusters. The corresponding nucleation rates were shown to be better than the those by the classical theory. Parametric studies were conducted to understand the effects of temperature and pressure.