Exploring the thermal decomposition of cigarette butts and its role in chromium adsorption processes

Smoked cigarette butts (SCB) can serve as precursors for producing activated carbon (AC) due to their high carbon content, which originates from cellulose acetate and other components retained during tobacco combustion. This study examines the pyrolysis process and char formation from SCB residue. Kinetic analysis of char formation is conducted using thermogravimetry with heating rates of 5, 10, and 15 °C/min. Mathematical models, including Kissenger-Akahira-Sunose (KAS), Starink (STK), and Ozawa-Flynn-Wall (OFW) are applied to determine thermodynamic parameters, such as activation energy. The resulting char undergoes KOH activation to enhance surface area and pore volume, resulting in BET surface area and micropore volume values of 433 m²/g and 0.25 cm³/g, respectively. The activated carbon is then used for Cr(VI) removal, exhibiting a maximum adsorption capacity (Q_max) of 55.8 mg/g, as determined by the Langmuir model.