A kinetic study on the abiotic methylation of divalent mercury in the aqueous phase


The mechanism and kinetics of the formation of methylmercury from an experimental solution containing divalent mercury and acetic acid has been investigated. The experiments were performed in a 2-dm3 Teflon reactor. The organic mercury was measured with time resolutions varying between minutes and hours, after derivatisation, gas chromatography separation and Cold vapour atomic fluorescence detection. (GC)-CVAFS. CVAFS technique was used for determination of inorganic mercury in the aqueous phase using an automated mercury analyser. The experiments were carried out in concentrations relevant for natural waters. Our result shows that the reaction proceeds via mercury acetate complexes. A first order reaction coefficient has been calculated at various pH values, and was found to be (9.0±0.9)P10-7 s-1 at pH 3.6-3.7. The rate was not found to be enhanced by UV-light when taking into account the photolytical degradation of methylmercury. The reaction rate at various pH values, the influences of some other relevant reaction parameters, and implications for atmospheric and terrestrial waters are discussed.

Medarbetare: John Munthe

Nyckelord: abiotic methylation, divalent mercury, aqueous phase

Typ: Artikel

År: 2010

Rapportnummer: A1824

Författare: Katarina Gårdfeldt, John Munthe, Dan Strömberg, Oliver Lindqvist

Publicerad i: The Science of The Total Environment, 2003. Volume 304, Issues 1-3, Pages 127-136