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Reductive Precipitation of Elemental Selenium from Selenious Acidic Solutions Using Sodium Dithionite / Nicolas Geoffroy in Industrial & engineering chemistry research, Vol. 48 N° 23 (Décembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 23 (Décembre 2009) . - pp. 10240–10246 Titre : Reductive Precipitation of Elemental Selenium from Selenious Acidic Solutions Using Sodium Dithionite Type de document : texte imprimé Auteurs : Nicolas Geoffroy, Auteur ; George P. Demopoulos, Auteur Année de publication : 2010 Article en page(s) : pp. 10240–10246 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Reductive--Precipitation--Elemental--Selenium--Selenious--Acidic--Solutions--Using  Sodium--Dithionite Résumé : In this work, the batch-reactor reduction of selenious acid (H2SeO3) species with sodium dithionite (Na2S2O4) from weakly acidic sulfate solutions containing 300 mg/L of selenium at 23 οC was studied. The results showed that, at an initial pH value of <1.7 and a dithionite stoichiometric excess of >3, <0.5 μg/L of selenium(IV) remained in solution after reduction. The reductive precipitation reaction started as soon as dithionite was added in the selenium-bearing solution and was completed within less than a minute. However, it was determined that the precipitate was not stable in the presence of the dithionite decomposition byproduct and partially redissolved after several hours. The reaction product, characterized using X-ray diffraction, scanning electron microscopy, and chemical analysis, was determined to be red amorphous selenium. The precipitate, in addition to elemental selenium, was determined to contain monoclinic sulfur that was apparently formed via a side reaction pathway involving the decomposition of dithionite. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9008502 [article] Reductive Precipitation of Elemental Selenium from Selenious Acidic Solutions Using Sodium Dithionite [texte imprimé] / Nicolas Geoffroy, Auteur ; George P. Demopoulos, Auteur . - 2010 . - pp. 10240–10246. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 23 (Décembre 2009) . - pp. 10240–10246 Mots-clés : Reductive--Precipitation--Elemental--Selenium--Selenious--Acidic--Solutions--Using  Sodium--Dithionite Résumé : In this work, the batch-reactor reduction of selenious acid (H2SeO3) species with sodium dithionite (Na2S2O4) from weakly acidic sulfate solutions containing 300 mg/L of selenium at 23 οC was studied. The results showed that, at an initial pH value of <1.7 and a dithionite stoichiometric excess of >3, <0.5 μg/L of selenium(IV) remained in solution after reduction. The reductive precipitation reaction started as soon as dithionite was added in the selenium-bearing solution and was completed within less than a minute. However, it was determined that the precipitate was not stable in the presence of the dithionite decomposition byproduct and partially redissolved after several hours. The reaction product, characterized using X-ray diffraction, scanning electron microscopy, and chemical analysis, was determined to be red amorphous selenium. The precipitate, in addition to elemental selenium, was determined to contain monoclinic sulfur that was apparently formed via a side reaction pathway involving the decomposition of dithionite. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9008502