Kinetics of the simultaneous oxidation of nickel(II) and sulfur(IV) by oxygen in alkaline medium in Ni(II)–sulfur(IV)–O2 system

• DOI: 10.1002/kin.20496
• Publication Date: 2010-06-08T16:43:23Z
• Authors: Anil Kumar Sharma; Punit Kumar Mudgal; S. P. Bansal; K. S. Gupta
• Keywords: Autoxidation

Abstract In the Ni(II)–S(IV)–O 2 system in region of pH > 8.4, both Ni(II) and S(IV) are simultaneously autoxidized, when sulfur is consumed fully NiOOH precipitates. At ethanol has no effect on rate, whereas ammonia strongly inhibits reaction 7.0. The kinetics reaction, presence absence ethanol, defined by rate law equation image where k constant, K O equilibrium constant for adsorption Ni(OH) particle surface. buffer, factor F , OH 1 3 4 stability constants NiSO NiOH + Ni(NH ) 2+ respectively. unbuffered medium, reduces to values sp were found be (1.3 ± 0.08) × 10 −1 s (4.2 3.5) −16 respectively, at 30°C. A nonradical mechanism that assumes SO 2− surface been proposed. ≤ 8.2, displays catalytic activity sulfur(IV)‐autoxidation it also not oxidized NiOOH. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 42: 464–478,