Investigation of the Dynamics and Kinetics Involved in Saline Aerosol Generation Under Air Erosion of Pure and Contaminated Halide Salts.

This study presents results from an investigation of the dynamics and kinetics involved in saline aerosol generation under air erosion of pure and contaminated halide salts. Investigations have been performed in a microhalochamber filled with active efflorescent pure or doped NaC1 salt granules. The performed work allows the suggestion that pure NaCl salt presents the highest potential to generate saline aerosols. The generation capacity of saline aerosols decreased in doped NaCl, and the efficiency of the doping salts to inhibit aerosol generation was in the order (KI-KCl)> KI approximate to KBr > KCl > CaCl2. Emission/erosion rate constants (min(-1)) were estimated by applying a simple kinetic treatment to the experimental data set (i.e. trends of In([S-0]/[S]) vs. time, where S represents the salt). The pseudo-first order erosion rate constant value (k(e)), characteristic of the emission/erosion of aerosol from salt granules, decreased in the order NaClpure (crystallite) > NaCldoped (with) (CaCl2) (or KCl) (salts) > NaCldoped with KBr (or) (KI salts). For the doping salt the emission/erosion rate constants varied in the order: ke((KI)) < k(e(KBr)) < k(e(KCl)) < ke((CaCl2)). The emission/erosion process is most probably controlled by the morphology of the used salt granules. The latter would be related to the solubility of the doping salt, the radii of the involved ions and the properties of the saline aqueous solutions that are used to obtain active efflorescent salt granules. Such properties could affect the surface enrichment of NaCl and of the doping salt, because surface composition is expected to play an important role at least in the first stage of the erosion process. The obtained results may have relevant implications in both atmospheric and medical fields.