کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4699691 1637661 2011 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Selenium chemical speciation in natural waters: Protonation and complexation behavior of selenite and selenate in the presence of environmentally relevant cations
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات ژئوشیمی و پترولوژی
پیش نمایش صفحه اول مقاله
Selenium chemical speciation in natural waters: Protonation and complexation behavior of selenite and selenate in the presence of environmentally relevant cations
چکیده انگلیسی

Selenium is an essential trace element. Selenium speciation in natural environmental conditions has been poorly studied, mostly because its relevance has been only recently acknowledged. In this work, a complete thermodynamic study on selenium(IV) and selenium(VI) was carried out. It includes the protonation equilibria of selenium anions in aqueous solution at 20 °C. The interaction of selenium anions with some metal ions that are normally encountered in environmental scenarios was also studied. The strategy involves the potentiometric study of all the equilibria using different ionic strength values of a non interacting electrolyte. Distribution species diagrams allow the prediction of the predominant species of selenium both under reducing or oxidizing conditions and in the presence of these metal ions. The dependence of the thermodynamic magnitudes on the ionic strength value is also evaluated. The speciation of Se(IV) or Se(VI), 10− 7 M, in the presence of mean concentrations of Ca2+ (16.5 mM) and Mg2+ (6.4 mM) shows the predominance of HSeO3−, [Ca(HSeO3)]+ and [Mg(HSeO3)]+, or of SeO42−, respectively. Results show that, depending on media pH and pE, interaction with metal ions can be either negligible or very important.


► Thermodynamic study on selenium(IV) and selenium(VI) in aqueous solution at 20 °C.
► Protonation equilibria of selenium anions and interaction with metal ions.
► Complete potentiometric study using different ionic strength values.
► pH and pE dependant interaction with metal ions in the environment.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Chemical Geology - Volume 288, Issues 1–2, 8 September 2011, Pages 32–38
نویسندگان
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