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Nafion-117 behavior during cation separation from spent chromium plating solutions / M. Elmuntasir I. Ahmed in Industrial & engineering chemistry research, Vol. 48 N° 14 (Juillet 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 14 (Juillet 2009) . - pp. 6805–6810 Titre : Nafion-117 behavior during cation separation from spent chromium plating solutions Type de document : texte imprimé Auteurs : M. Elmuntasir I. Ahmed, Auteur ; Kuo-Lin Huang, Auteur ; Thomas M. Holsen, Auteur Année de publication : 2009 Article en page(s) : pp. 6805–6810 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Nafion-117  ion-exchange  membranes  Spent  chromium  plating  solutions Résumé : This study investigated the behavior of Nafion-117 ion-exchange membranes that are commonly used as the separator in electrolytic regeneration of spent chromium plating solutions. In the co-presence of Cu2+, Ni2+, and Fe3+ impurities (∼0.01−0.1 M) in ∼0.5−2.0 M H2CrO4, the exchange equivalents of Ni2+ by Nafion-117 was double that of Cu2+ (0.02 mmol of H+/(g of Nafion)) but smaller than that (∼0.03−0.15 mmol of H+/(g of Nafion)) of Fe3+, exhibiting the order Fe3+ ≥ Ni2+ ≥ Cu2+ in Nafion affinity. The water content (∼41%) of a Nafion-117 membrane soaked in 2 M H2CrO4 was greater than those (∼35−38%) in the contaminated 2 M chromic acid solutions, whereas the porosity (0.24) of the former was smaller than those (0.29−0.37) of the latter. For the Nafion-117 in 2 M chromic acid solutions with/without cation impurities, (1) the tortuosity coefficient of Fe3+ was about 1.8 times that of Cu2+ or Ni2+, (2) the calculated pore radius was 3.2 nm for a multiimpurity case (0.1 M Cu(II), Fe(III), Ni(II), and Cr(III) each) based on the Gierke’s model, and (3) the cation impurities did not significantly influence the numbers of water molecules in Nafion clusters. The Nafion-117 withstood the pH < 0 environment with only minor rotation in the fluorocarbon backbone due to accommodation of anionic Cr(VI) within clusters. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900149a [article] Nafion-117 behavior during cation separation from spent chromium plating solutions [texte imprimé] / M. Elmuntasir I. Ahmed, Auteur ; Kuo-Lin Huang, Auteur ; Thomas M. Holsen, Auteur . - 2009 . - pp. 6805–6810. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 14 (Juillet 2009) . - pp. 6805–6810 Mots-clés : Nafion-117  ion-exchange  membranes  Spent  chromium  plating  solutions Résumé : This study investigated the behavior of Nafion-117 ion-exchange membranes that are commonly used as the separator in electrolytic regeneration of spent chromium plating solutions. In the co-presence of Cu2+, Ni2+, and Fe3+ impurities (∼0.01−0.1 M) in ∼0.5−2.0 M H2CrO4, the exchange equivalents of Ni2+ by Nafion-117 was double that of Cu2+ (0.02 mmol of H+/(g of Nafion)) but smaller than that (∼0.03−0.15 mmol of H+/(g of Nafion)) of Fe3+, exhibiting the order Fe3+ ≥ Ni2+ ≥ Cu2+ in Nafion affinity. The water content (∼41%) of a Nafion-117 membrane soaked in 2 M H2CrO4 was greater than those (∼35−38%) in the contaminated 2 M chromic acid solutions, whereas the porosity (0.24) of the former was smaller than those (0.29−0.37) of the latter. For the Nafion-117 in 2 M chromic acid solutions with/without cation impurities, (1) the tortuosity coefficient of Fe3+ was about 1.8 times that of Cu2+ or Ni2+, (2) the calculated pore radius was 3.2 nm for a multiimpurity case (0.1 M Cu(II), Fe(III), Ni(II), and Cr(III) each) based on the Gierke’s model, and (3) the cation impurities did not significantly influence the numbers of water molecules in Nafion clusters. The Nafion-117 withstood the pH < 0 environment with only minor rotation in the fluorocarbon backbone due to accommodation of anionic Cr(VI) within clusters. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900149a