Sustainable valorisation of cigarette butts waste through pyrolysis: An insight into the pyrolytic products and subsequent aqueous heavy metals removal by pyrolytic char

In this study, cigarette butts (CB) waste was pyrolyzed over a wide temperature range (400–700 °C) using Pyro/GC–MS and slow pyrolysis experiments. The feedstock and char products were extensively investigated using TGA, elemental analysis, surface area and porosity analysis, SEM-EDS, XRD, and FT-IR, and subsequently tested for their ability to remove Ni (II) and Cu (II) from aqueous solutions. The Pyro/GC–MS analysis revealed the presence of several useful compounds including acids, esters and hydrocarbons. Char yields ranged from 26.6 to 20.1 wt%, and carbon contents varied from 65.3 to 60.8 wt%. The chars produced at medium temperatures (500-600 °C) were highly porous, with a specific surface area of 272.9–270.8 m²/g. The heavy metal adsorption studies revealed that CB 500 °C had the highest adsorption capacity of 13.8 mg/g with 53.4 % nickel removal, while CB 600 °C had the highest adsorption capacity of 23.4 mg/g with 94.7 % copper removal.