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- Title
Specificity of Terbium(III) Oxidation by Persulfate Ions in the Presence of Unsaturated Phosphotungstate K<sub>10</sub>P<sub>2</sub>W<sub>17</sub>O<sub>61</sub>.
- Authors
Shilov, V. P.; Fedoseev, A. M.
- Abstract
The oxidation of Tb(III) by persulfate ions in solutions of unsaturated phosphotungstate K10P2W17O61 (L) was studied by spectrophotometry. The accumulation of Tb(IV) is observed at pH < 3. The yield of Tb(IV) depends on pH and [L]. The maximum yield is observed in solutions with pH 1.5–2.5 and [L] > 6×10–4 M. The accumulation of Tb(IV) proceeds as a zero-order reaction with respect to [Tb(III)] and a first-order reaction with respect to [S2O82–]. The reaction rate increases with the increase in pH from 0.91 to 1.5–1.9; an increase in pH to 2.44 decreases the rate. The activation energy (42–60°С) is estimated at 140 kJ/mol. The reaction mechanism includes the decomposition of S2O82– ions into SO4– radical ions, which are converted into OH˙ radicals, which oxidize Tb(III) bound in a complex with L (1 : 1). In parallel, the catalytic decomposition of S2O82– ions occurs, which leads to the formation of Caro's acid H2SO5. Its hydrolysis generates Н2О2, a reducing agent for Tb(IV). In addition, Tb(IV) is reduced by water. It was not possible to oxidize thulium(III) under the conditions of terbium(IV) formation.
- Subjects
TERBIUM; RADICAL ions; IONS; ACTIVATION energy; OXIDATION; REDUCING agents
- Publication
Russian Journal of General Chemistry, 2022, Vol 92, Issue 11, p2511
- ISSN
1070-3632
- Publication type
Article
- DOI
10.1134/S107036322211038X