Upgrading waste tires by chemical activation for the capture of SO2

Waste tires have been upgraded as activated carbon by chemical activation with KOH at different KOH:tire ratios, 0:1, 0.5:1, 1:1 and 4:1, namely AC-0, AC-0.5, AC-1 and. AC-4 and characterized in terms of elemental and proximate analyses, nitrogen adsorption/desorption, acid/base and Boehm titrations. An increase in activating agent:tire ratio resulted in an increase in the fixed carbon content, surface area and pore volume, and a decrease in surface basicity and sulfur content. The so -prepared materials were tested in the adsorption of SO2, as an important pollutant from fuel combustion, using a thermogravimetric analyzer. The final adsorption capacity followed the trend AC -0 < AC -0.5 < AC -1 < AC -4, matching that of increasing surface area and pore volume, while adsorption affinity was impacted by both textural and acid/base properties. A kinetic model with statistical validation based on Ritchie's equation successfully matched the transient uptake data, where larger rate constant values were obtained for those carbons presenting higher surface basicity. (C) 2016 Elsevier B.V. All rights reserved.