Reactive adsorption of SO2 on activated carbons with deposited iron nanoparticles

► Prehumidification of carbon surface increases two and half times the uptake of SO2. ► H2SO4 is the product of SO2 reactive adsorption on the unmodified carbon surface. ► Iron species react with H2SO4 forming sulfates. ► Small iron nanoparticles enhanced adsorption by providing well-dispersed reactive centers.