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Gamma-radiation induced formation of chromium oxide nanoparticles from dissolved dichromate.
MedLine Citation:
PMID:  23147715     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
The formation of chromium oxide nanoparticles by gamma radiolysis of Cr(VI) (CrO(4)(2-) or Cr(2)O(7)(2-)) solutions was investigated as a function of pH and initial Cr(VI) concentration by measuring [Cr(VI)], the particle concentration ([Cr(III)(col)]) and [H(2)], and by characterizing the particles using TEM, Raman, FTIR and XPS. The results show that Cr(VI) is easily reduced to Cr(III) by a homogeneous aqueous reaction with ˙e(aq)(-), but, due to the stability of Cr(III) colloids, the growth of the Cr(OH)(3) particles is very slow. As the particles grow the interior of the particle dehydrates to form Cr(2)O(3) while the outer layer remains hydrated. When most of the Cr(VI) that is initially present in the solution is converted to Cr(OH)(3) further redox reactions of chromium species occur on the particle surfaces. The redox system reaches a pseudo-equilibrium state due to cyclic reactions of Cr(III) with ˙OH and H(2)O(2), and reactions of Cr(VI) with ˙e(aq)(-) and H(2)O(2). The size distribution of the particles that are formed is controlled by these solution-solid interface reactions.
Authors:
L M Alrehaily; J M Joseph; A Y Musa; D A Guzonas; J C Wren
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-11-13
Journal Detail:
Title:  Physical chemistry chemical physics : PCCP     Volume:  -     ISSN:  1463-9084     ISO Abbreviation:  Phys Chem Chem Phys     Publication Date:  2012 Nov 
Date Detail:
Created Date:  2012-11-13     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100888160     Medline TA:  Phys Chem Chem Phys     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Affiliation:
Department of Chemistry, The University of Western Ontario, London, Ontario, CanadaN6A 5B7. jcwren@uwo.ca.
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