Kinetics of absorption of sulfur dioxide and nitric oxide in aqueous mixed solutions of sodium chlorite and sodium hydroxide.

Abstract

The rates of single and simultaneous absorptions of dilute SO₂ and NO in aqueous mixed solutions of NaClO₂ and NaOH were measured at 25°C using a stirred vessel with a plain gas-liquid interface. In the SO₂-NaClO₂ system, the absorption rate exceeded the gas-film controlled rate, which implies the possibility of gas-phase oxidation of SO₂ due to the evolved C1O₂. In the SO₂-(NaClO₂+NaOH) system, the absorption rate agreed with that under gas-film controlled conditions. In the (SO₂+NO)-(NaClO₂+NaOH) system, the reduction of the NO absorption rate in the presence of SO₂ substantially exceeded that evaluated through the decrease in interfacial concentration of NaClO₂ and NaOH due to surface reaction with coexisting SO₂. The rate of absorption of SO₂ exceeded the gas-film controlled rate. The decomposition of NaClO₂ proceeds to a greater degree during simultaneous absorption than the single absorption of SO₂.