Physicochemical and Photosorption Properties of Oxygen-containing Calcium Compounds – Components of Troposferic Aerosol

摘要

The importance of this paper is determined by the research of conditions of photosorption processes occurance on the surface of aerosol particles resulting in the removal of toxic substances from the atmosphere. Acid-base properties of oxygen-containing calcium compounds being components of troposphere aerosol particles were studied by methods of pHmetry and Hammet's indicators. The basic properties of the investigated compounds surfaces are predominant ones: pH_(iis) of calcium oxide and hydroxide has a value of 9.3 – 9.5, and that for carbonate and calcite equals to 12.3-12.4. Indicator method distinguishes three areas of spectrum corresponding to Lewis base, and Brensted neutral and basic centers. The intencity of peaks is much higher for Ca(OH)_2 and CaO. The interaction process of halogen-containing organic compounds (Freons: 134a, 22 and 12) with calcium carbonate surface under illumination in conditions close to tropospheric conditions was studied. It is shown that the interaction is the destructive photosorption of Freons (134a or 22). The spectral dependence of effective quantum yield of destructive photosorption is determined. As a result of the interaction calcium fluoride and calcium chloride are formed at the surface.