SO2 adsorption by activated carbons with various burnoffs obtained from a bituminous coal Original Research Article

Activated carbons, obtained from pyrolysis and CO2 activation of both a bituminous coal and its reduced ash content derivative produced by HCl and HF treatment, were used to show that SO2 sorbent characteristics are improved by increasing their degree of burnoff and are related to their content of surface sites with acidic and basic features, their surface area, and their pore size distribution. Active carbons with reduced ash content also show better SO2 sorption properties at lower burnoff values and a better retention of their initial SO2 sorbent activity after ten adsorption–desorption cycles. Their improved behaviour is related to the presence of pores with larger dimensions and to a redistribution of the metals in the original mineral matter on the carbonaceous matrices induced by acid washing.