Coal-Based Activated Carbons for the Removal of Sulphur Dioxide via Adsorption

Abstract

Zinc chloride-activated carbons and steam-activated carbons were prepared from Maghara coal. The textural properties were determined from low-temperature nitrogen adsorption. Zinc chloride activation is usually associated with the creation of new micropores while steam activation involves pore widening particularly when the percentage burn-off is high. The adsorption of SO 2 on steam-activated carbon is high compared with ZnCl 2 -activated carbons. Steam activation develops surface basic groups which provide chemisorption sites for SO 2 . The adsorption of SO 2 is enhanced in the presence of O 2 and water vapour and involves the formation of sulphuric acid in this case. Sulphur dioxide adsorption is related to the chemistry of the carbon surface rather than to the extent of the surface area of the activated carbon.