Photochemical behavior of inorganic and organic selenium compounds in various aqueous solutions

摘要: Selenium possesses interesting chemical, biochemical and geochemical behaviors. However, studies of its photochemical properties in aqueous systems are scarce. A better understanding these phenomena is great importance for further application such to selenium speciation. In this work, the behavior some organic compounds have been systematically studied various matrices under UV irradiation at 300 nm. It was observed that oxidation rate Se(IV) Se(VI) greatly enhanced presence HN03 ≥1 × 10 −3 M, but not by NaNO3. However photo-oxidation could be inhibited Cl − . Under irradiation, organoselenium went through two successive reactions pure water: a direct photolysis (photo-cleavage) followed form Se(VI). These steps also accelerated NO3 although second step required an acidic condition. The photo cleavage rates varied from one compound another 10-fold differences were observed. Similarly Se(IV), prevented all compounds. Detailed reaction mechanisms involving OH radicals proposed explain Se behaviors different matrices. © 2005 Elsevier B.V. All rights reserved.