Studies Of Interface Electrochemistry And Desorption Of Hg, As And Pb Of Atmospheric Particulate Matter

Along with the development of industry, the environment pollution is gradually serious, thereinto the air pollution is one of environmental problems that caused dramatical attention. The urban atmospheric particulate matters carried the various kinds of heavy metals was an important route of heavy metals' long distance migration, because atmospheric particulate matters have long distance migratory property. Atmospheric particulate matters contact with soils and water resources after their settlement bring pollution to ground environment.The interface electrochemistry and the desorption of Hg, As and Pb of the particulate matters have an important effect on the environmental action of heavy metals, eg.speciation, transformation, fate et al. These aspects were important research content, and have not been reported by other researchers. The sample is airborne particles in this paper, the speciation of heavy metals, interface electrochemistry and the desorption of Hg, As and Pb of particulate matters were systemically studied, increasing the knowledge of atmospheric particulate matters environmental behaviors. The research contents and conclusions were as follows:(1) Characterization of particulate matters, eg.chemical component analysis, the content of Hg, As, Pb in the particulate matters, specific area , distribute of particle size, TOC were studied.(2) The point of zero net charge (PZNC) and structural charge density (σ_st) of atmospheric particulate matters were measured by mass titration and formaldehyde condensation method, respectively, showing that the atmospheric particulate matter sample studied possesses structural negative charges (σ_st=-0.18mmol/g), and there is a PZNC independent of electrolyte concentration (pH_PZNC=8.00). According to the values of pH_PZNC, the total density of surface proton-active sites (Ns) and σ_st, the intrinsic surface reaction equilibriumconstants, pK of 1-pK model, pK_a1^int and pK_a2^int of 2-pK model, were directly calculated to be 8.00, 2.07 and 13.93, respectively, for the atmospheric particulate matter sample studied. (3) In this paper, speciations of Hg, As, Pb in the particulate matters were studied by Tessier method and BCR method respectively, found that the speciation rules of Hg, As are same, the order was exchangeable< carbonates