Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7642686 | Microchemical Journal | 2014 | 9 Pages |
Abstract
A redox speciation and preconcentration study of Cr(III) and Cr(VI) using a flow injection system with dual mini-columns prepared from cross-linked polymers-poly(methacrylic acid) and polyvinylimidazole was developed. Characterization of organic polymers was performed by using FTIR, SEM, TG, C:H:N and BET measurements. The equilibrium data obtained from Cr(III) adsorption on poly(methacrylic acid) and Cr(VI) on polyvinylimidazole were fitted very well to the dual site Langmuir-Freundlich model, suggesting the presence homogeneous and heterogeneous binding site and providing maximum adsorption capacities of 1.42 and 3.24 mg gâ 1, respectively. The adsorption kinetics data were described by the pseudo-second-order model for both polymers, thus corroborating to isotherm data. The on-line preconcentration/speciation system was operated by loading 18.0 mL of a solution containing Cr(III) and Cr(VI) at pH 4.0 through the dual mini-columns at a flow rate of 3.0 mL minâ 1, where Cr(III) was selectively retained on poly(methacrylic acid), while Cr(VI) was retained on polyvinylimidazole. The limits of detection were found to be 0.84 and 1.58 μg Lâ 1 for Cr(III) and Cr(VI), respectively. The preconcentration factor (PF), consumptive index (CI) and concentration efficiency (CE) were found to be 47.3/8.6, 0.38/2.1 mL and 7.88/1.43 minâ 1 for Cr(III) and Cr(VI), respectively. The developed method was successfully applied to the speciation of chromium in different kinds of water samples. Satisfactory recovery values ranging from 89.9 to 108.3% were obtained.
Related Topics
Physical Sciences and Engineering
Chemistry
Analytical Chemistry
Authors
Marcela Zanetti Corazza, Emerson Schwingel Ribeiro, Mariana Gava Segatelli, Cesar Ricardo Teixeira Tarley,