ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Adsorption of SO₂ on alumina

P. Fellner, J. Jurišová, V. Khandl, A. Sýkorová, and J. Thonstad

Department of Inorganic Technology, Faculty of Chemical and Food Technology, Slovak University of Technology, SK-812 37 Bratislava, Slovakia

E-mail: pavel.fellner@stuba.sk

Received: 2 December 2005  Revised: 9 February 2006  Accepted: 9 February 2006

Abstract: The adsorption of SO₂ on alumina used in the aluminium industry, the so-called smelter-grade alumina, was studied in the temperature range 15–120°C. It was found that at temperatures lower than 40°C, sulphur dioxide was bonded to alumina reversibly by physical forces, and the adsorption could be described satisfactorily by the Langmuir adsorption isotherm. The heat of adsorption was estimated to be −33 kJ mol⁻¹. At temperatures ranging from 80°C to 120°C, which prevail in dry scrubbers in the aluminium industry, the heat of adsorption was determined to be −56 kJ mol⁻¹. When SO₂ was adsorbed at temperatures higher than 80°C, about 30 % of the SO₂ could not be desorbed even if the samples were heated up to 250°C. In the presence of SO₂ and oxygen, the formation of sulphate was observed at temperatures above 90°C.

Keywords: adsorption equilibrium - sulphur dioxide - alumina - Langmuir isotherm - Freundlich isotherm

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-006-0055-3

Chemical Papers 60 (4) 311–314 (2006)