engleski

Electrochemical study of surface active material in atmospheric aerosols

Monitoring chemical composition of atmospheric aerosols has attracted attention of numerous investigators. However, the knowledge on organic aerosol chemistry is less advanced compared to that on inorganic chemistry. Organic matter in atmosphere is a result of primary anthropogenic and biogenic emissions and/or of transformation processes of different precursors. Surface active substances (SAS) can form monomolecular films at the different interfaces influencing thus the interfacial properties of atmospheric droplets. SAS influence the condensation processes and accumulation of pollutants in aerosols enhancing thus the potential of rain for washing out organic matter from the atmosphere. The atmospheric input of substances in limnological and marine ecosystems dominates on regional and global scale, having an important role in controlling the level and the dynamics of persistent organic pollutants in aquatic systems. In this work content of SAS was measured in the aerosol samples collected in two cities in Croatia, one in the continent and the other in coastal zone in the Middle Adriatic. The electrochemical techniques were introduced for the first time in measurements of SAS in atmospheric aerosols. The measurement of the electrode double layer capacity changes offers the possibility of direct investigation of adsorption characteristics of a complex mixture of naturally present organics at the electrode-electrolyte interface. Additional characterization of organic matter was performed by using electrochemical probes, namely lead and cadmium ions representing major heavy metal pollutants in natural waters. The adsorption of organic molecules can influence the electrode processes of metal ions through inhibition of electrode process, accumulation of metal ion in the adsorption layer or formation of layer transparent for metal transfer. Adsorption characteristics of SAS present in real samples will be compared with the selected model substances, relevant for organic constituents of atmospheric systems, and the role of humic like substances (HULIS) in transport processes will be elaborated.

aerosol ; electrochemistry ; organic matter ; surface active substances

http://www.colloidsandmaterials.com/pdf/ColloidsandMaterials2011_posterprogramme.pdf