Effect of Temperature on Production of Sulfite by Absorption of Sulfur Dioxide with Oxygen

Abstract

In order to produce sulfites from SO₂ contained in flue gases, an SO₂ absorption experiment was conducted using a gas mixture, containing oxygen that emulates industrial flue gases. Concentrations of sulfite and sulfate produced by SO₂ absorption were measured by HPLC, and their production ratios were assessed at temperatures between 288 K and 333 K. As a result, the absorption product was mostly sulfate irrespective of temperature when SO₂ was absorbed using a liquid absorbent with a pH of over 6; however, sulfite ions were produced when the pH was around 4. When SO₂ absorption was carried out using an absorbent with a pH of under 4, sulfate was produced at a temperature of 333 K, but sulfite was produced at temperatures below 303 K.