A novel micro-sphere activated carbon synthesized from waste cigarette butts for ammonia adsorption.

Waste cigarette filters mainly contain hardly degradable cellulose acetate, toxic nicotine, and traces of heavy metals, and therefore cause environmental pollution hazards when discarded. In order to convert cigarette butt waste into a valuable product, this article investigates the preparation of activated carbon from cigarette butts via a two-step process of hydrothermal reaction and a subsequent chemical activation with phosphoric acid as an activator. During hydrothermal reaction, it was found that a process of decarboxylation and dehydration cleavage of acetate occurs, leading to micron fragments and subsequent agglomeration into carbonaceous micro-spheres. The cigarette-butts-derived activated carbon micro-spheres have a high BET surface area of ∼ 1406 m/g and NH adsorption capacity of ∼ 35.9 mg/g. It was revealed that the ammonia adsorption capacity tends to be positively and linearly correlated with the acidic functional group content of the activated carbon surface while negatively with BET surface area.