| Titre : | Solid phasepre - concentration of cobalt (II) using pyridine – thiocyanate reagents : X - ray crystal structure of the extracted ternary cobalt (II) complex (2012) |
| Auteurs : | Raja Saha, Auteur ; Animesh Sahana, Auteur ; Sudipta Das, Auteur |
| Type de document : | Article : texte imprimé |
| Dans : | Chemical engineering journal (Vol. 174 N° 1, Octobre 2011) |
| Article en page(s) : | pp.58-67 |
| Note générale : | Génie chimique |
| Langues : | Anglais |
| Tags : | Co(II) Pyridine-2,6-dimethanol Thiocyanate Crystalstructure Chelation Flame atomic absorption spectrometry |
| Résumé : | Mixture of pyridine-2,6-dimethanol (PDM) and thiocyanate (SCN−) (1:1, mole ratio) immobilized on silica served as a very efficient sorbent for selective retention of Co(II) from other associated metal ions at trace level. The maximum sorption capacity for Co(II) was found to be 0.203 mmol g−1 at pH 9.0. Sorbed Co(II) was completely eluted by 3.5 mL of 3 mol L−1 HCl and measured using flame atomic absorption spectrometer (FAAS). The structure of the extracted Co(II) complex was confirmed by single crystalX-raystructure and Fourier transform infrared (FTIR) spectroscopy. Thermo gravimetric analysis (TGA) of the chelated Co(II) complex revealed its stability at the optimum extraction temperature (55 °C). The method was reproducible with a relative standard deviation (RSD) of 0.6% (N = 10) with three sigma detection limit (N = 10) of 0.6 μg g−1. A pre-concentration factor, 94 was achieved. Interferences from Mn2+ and Cu2+ ions were eliminated by prior oxidation of Mn2+ by KIO4 to MnO4− and masking of Cu2+ with NH4SCN, respectively. A plausible mechanism for the selective extraction of Co(II) was attributed to the formation of a first order water insoluble inner–metallic complex as confirmed by the single crystalX-raystructure analysis. The developed method has been tested for trace level separation and estimation of cobalt in some certified reference materials. Analyses of some biological and environmental samples were performed. |
| ISSN : | 1385-8947 |
| En ligne : | http://www.sciencedirect.com/science/article/pii/S1385894711009910 |
