Porous carbons as solid-state adsorbents have recently attracted considerable interest in the areas of storage and capture of CO2 as well as the adsorption of radioactive matters. In this work, cigarette butts, one kind of common wastes referring to the filters, were utilized to prepare highly porous carbons by KOH activation in argon atmosphere. The resulting porous carbon shows a high specific surface area of up to 2751 m(2) g(-1) with abundant micropores. The resulting porous carbon exhibits excellent iodine uptake of 262 wt% and high CO2 adsorption capacity of 6.0 mmol g(-1) at ambient pressure and 273 K, which both are among the highest values reported to date. Given these excellent iodine uptake, CO2 adsorption capacity, ease of preparation as well as good physiochemical stability, the porous carbons derived from cigarette butts show great potential in the reversible adsorption of radioactive iodine and CO2. (C) 2016 Elsevier B.V. All rights reserved.