Kinetics of Catalytic Oxidation of Sulfite in Diluted Aqueous Solutions

• Published in: Chemical engineering & technology Vol. 38; no. 11; pp. 1919 - 1924
• Main Authors: Opletal, Michal, Novotný, Petr, Rejl, František J., Moucha, Tomáš, Kordač, Michal
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.11.2015; WILEY‐VCH Verlag
• Subjects: Aqueous solutions; Catalysts; Deoxygenation; Dilution; Gas-liquid reactions; Loop reactor; Mass transfer; Oxidation; Reaction kinetics; Reaction order; Reaction rate; Sulfites
• ISSN: 0930-7516; 1521-4125
• DOI: 10.1002/ceat.201500064

The reaction kinetics for low concentrations of sulfite close to the stoichiometric ration of oxygen was investigated in a rapid‐mixing apparatus. Air‐ or pure oxygen‐saturated solution containing the catalyst was mixed with aqueous sulfite solution. Mixing ratios with stoichiometric excess of dissolved oxygen were tested. Reaction orders for sulfite, oxygen, and a Co(II) catalyst from literature were confirmed in the tested concentration range. The apparent kinetic constant and activation energy data are presented. The high importance of proper mixing of the two reacting solutions is reported, which was revealed during the development of the precise experimental technique providing reliable kinetic data. A method of partial deoxygenation is developed to circumvent complex liquid recycling during mass transfer measurement in pilot‐scale multiphase loop reactors. Apparent kinetic parameters of diluted sodium sulfite oxidation in aqueous solution at high oxygen‐to‐sulfite ratio are presented. The application of a rapid mixing apparatus for studying very fast reactions is described.