Dissolution of nickel ferrite in aqueous solutions containing oxalic acid and ferrous salts
The dissolution of nickel ferrite in oxalic acid and in ferrous oxalate- oxalic acid aqueous solution was studied. Nickel ferrite was synthesized by thermal decomposition of a mixed tartrate; the particles were shown to be coated with a thin ferric oxide layer. Dissolution takes place in two stages,...
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todo:paper_00219797_v225_n2_p403_Figueroa2023-10-03T14:25:10Z Dissolution of nickel ferrite in aqueous solutions containing oxalic acid and ferrous salts Figueroa, C.A. Sileo, E.E. Morando, P.J. Blesa, M.A. Dissolution Ferrous oxalate Mixed oxides Nickel ferrite Oxalic acid Surface complexation ferric oxide ferrous ion iron nickel oxalic acid tartaric acid aqueous solution article catalysis dissolution oxidation reduction reaction priority journal X ray diffraction The dissolution of nickel ferrite in oxalic acid and in ferrous oxalate- oxalic acid aqueous solution was studied. Nickel ferrite was synthesized by thermal decomposition of a mixed tartrate; the particles were shown to be coated with a thin ferric oxide layer. Dissolution takes place in two stages, the first one corresponding to the dissolution of the ferric oxide outer layer and the second one being the dissolution of Ni1.06Fe1.96O4. The kinetics of dissolution during this first stage is typical of ferric oxides: in oxalic acid, both a ligand-assisted and a redox mechanism operates, whereas in the presence of ferrous ions, redox catalysis leads to a faster dissolution. The rate dependence on both oxalic acid and on ferrous ion is described by the Langmuir-Hinshelwood equation; the best fitting corresponds to K(1/ads) = 25.6 mol-1 dm-3 and k(1/max) = 9.17 x 10-7 mol m-2 s-1 and K(2/ads) = 37.1 x 103 mol-1 dm-3 and k(1/max) = 62.3 x 10-7 mol m-2 s-1, respectively. In the second stage, Langmuir- Hinshelwood kinetics also describes the dissolution of iron and nickel from nickel ferrite, with K(1/ads) = 20.8 mol-1 dm3 and K(2/ads) = 1.16 x 105 mol-1 dm3. For iron, k(1/max) = 1.02 x 10-7 mol of Fe m-2 s2+-1 and k(2/max) = 2.38 x 10-7 mol of Fe m-2 s-1; for nickel, the rate constants k(1/max) and k(2/max) are 2.4 and 1.79 times smaller, respectively. The factor 1.79 agrees nicely with the stoichiometric ratio, whereas the factor 2.4 implies the accumulation of some nickel in the residual particles. The rate of nickel dissolution in oxalic acid is higher than that in bunsenite by a factor of 8, whereas hematite is more reactive by a factor of 9 (in the absence of Fe(II)) and 27 (in the presence of Fe (II)). It may be concluded that oxalic acid operates to dissolve iron, and the ensuing disruption of the solid framework accelerates the release of nickel. (C) 2000 Academic Press. Fil:Sileo, E.E. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00219797_v225_n2_p403_Figueroa |
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Universidad de Buenos Aires |
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I-28 |
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R-134 |
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
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Dissolution Ferrous oxalate Mixed oxides Nickel ferrite Oxalic acid Surface complexation ferric oxide ferrous ion iron nickel oxalic acid tartaric acid aqueous solution article catalysis dissolution oxidation reduction reaction priority journal X ray diffraction |
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Dissolution Ferrous oxalate Mixed oxides Nickel ferrite Oxalic acid Surface complexation ferric oxide ferrous ion iron nickel oxalic acid tartaric acid aqueous solution article catalysis dissolution oxidation reduction reaction priority journal X ray diffraction Figueroa, C.A. Sileo, E.E. Morando, P.J. Blesa, M.A. Dissolution of nickel ferrite in aqueous solutions containing oxalic acid and ferrous salts |
| topic_facet |
Dissolution Ferrous oxalate Mixed oxides Nickel ferrite Oxalic acid Surface complexation ferric oxide ferrous ion iron nickel oxalic acid tartaric acid aqueous solution article catalysis dissolution oxidation reduction reaction priority journal X ray diffraction |
| description |
The dissolution of nickel ferrite in oxalic acid and in ferrous oxalate- oxalic acid aqueous solution was studied. Nickel ferrite was synthesized by thermal decomposition of a mixed tartrate; the particles were shown to be coated with a thin ferric oxide layer. Dissolution takes place in two stages, the first one corresponding to the dissolution of the ferric oxide outer layer and the second one being the dissolution of Ni1.06Fe1.96O4. The kinetics of dissolution during this first stage is typical of ferric oxides: in oxalic acid, both a ligand-assisted and a redox mechanism operates, whereas in the presence of ferrous ions, redox catalysis leads to a faster dissolution. The rate dependence on both oxalic acid and on ferrous ion is described by the Langmuir-Hinshelwood equation; the best fitting corresponds to K(1/ads) = 25.6 mol-1 dm-3 and k(1/max) = 9.17 x 10-7 mol m-2 s-1 and K(2/ads) = 37.1 x 103 mol-1 dm-3 and k(1/max) = 62.3 x 10-7 mol m-2 s-1, respectively. In the second stage, Langmuir- Hinshelwood kinetics also describes the dissolution of iron and nickel from nickel ferrite, with K(1/ads) = 20.8 mol-1 dm3 and K(2/ads) = 1.16 x 105 mol-1 dm3. For iron, k(1/max) = 1.02 x 10-7 mol of Fe m-2 s2+-1 and k(2/max) = 2.38 x 10-7 mol of Fe m-2 s-1; for nickel, the rate constants k(1/max) and k(2/max) are 2.4 and 1.79 times smaller, respectively. The factor 1.79 agrees nicely with the stoichiometric ratio, whereas the factor 2.4 implies the accumulation of some nickel in the residual particles. The rate of nickel dissolution in oxalic acid is higher than that in bunsenite by a factor of 8, whereas hematite is more reactive by a factor of 9 (in the absence of Fe(II)) and 27 (in the presence of Fe (II)). It may be concluded that oxalic acid operates to dissolve iron, and the ensuing disruption of the solid framework accelerates the release of nickel. (C) 2000 Academic Press. |
| format |
JOUR |
| author |
Figueroa, C.A. Sileo, E.E. Morando, P.J. Blesa, M.A. |
| author_facet |
Figueroa, C.A. Sileo, E.E. Morando, P.J. Blesa, M.A. |
| author_sort |
Figueroa, C.A. |
| title |
Dissolution of nickel ferrite in aqueous solutions containing oxalic acid and ferrous salts |
| title_short |
Dissolution of nickel ferrite in aqueous solutions containing oxalic acid and ferrous salts |
| title_full |
Dissolution of nickel ferrite in aqueous solutions containing oxalic acid and ferrous salts |
| title_fullStr |
Dissolution of nickel ferrite in aqueous solutions containing oxalic acid and ferrous salts |
| title_full_unstemmed |
Dissolution of nickel ferrite in aqueous solutions containing oxalic acid and ferrous salts |
| title_sort |
dissolution of nickel ferrite in aqueous solutions containing oxalic acid and ferrous salts |
| url |
http://hdl.handle.net/20.500.12110/paper_00219797_v225_n2_p403_Figueroa |
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