Commercial anion exchange resin modified with azolates for remarkable separation of SO2 from CO2

•Commercial Amberlite® IRA-900 was modified with azolates for reversible SO2 capture.•IRA-900 (TetrZ) displays remarkable performance for the separation of SO2 from CO2.•IRA-900 (TetrZ) is the top one in terms of SO2/CO2 selectivities among solid materials.•IRA-900 (TetrZ) is highly reversible for SO2 adsorption, and can be reused for many times.•Remarkable performance is due to the multiple-site strong interaction of tetrazolate with SO2.