کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
10529011 960770 2005 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Photochemical behavior of inorganic and organic selenium compounds in various aqueous solutions
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آنالیزی یا شیمی تجزیه
پیش نمایش صفحه اول مقاله
Photochemical behavior of inorganic and organic selenium compounds in various aqueous solutions
چکیده انگلیسی
Selenium possesses interesting chemical, biochemical and geochemical behaviors. However, studies of its photochemical properties in aqueous systems are scarce. A better understanding of these phenomena is of great importance for further application of such properties to selenium speciation. In this work, the photochemical behavior of selenium and some of its organic compounds have been systematically studied in various aqueous matrices under UV irradiation at 300 nm. It was observed that the photochemical oxidation rate of Se(IV) to Se(VI) was greatly enhanced in the presence of HN03 at ≥1 × 10−3 M, but not by NaNO3. However this photo-oxidation could be inhibited by the presence of Cl−. Under UV irradiation, organoselenium compounds went through two successive photochemical reactions in pure water: a direct photolysis (photo-cleavage) followed by a photo-oxidation to form Se(VI). These two steps could also be greatly accelerated in presence of NO3− although the second step required an acidic condition. The photo cleavage rates varied from one organic compound to another and 10-fold differences were observed. Similarly to Se(IV), the further oxidation to Se(VI) could be prevented by Cl− for all studied organoselenium compounds. Detailed reaction mechanisms involving OH radicals are proposed to explain Se photochemical behaviors in different matrices.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Analytica Chimica Acta - Volume 545, Issue 2, 27 July 2005, Pages 149-157
نویسندگان
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