Recovery of cellulose acetate bioplastic from cigarette butts: realization of a sustainable sorbent for water remediation

Cigarette butts, one of the most common forms of litter in the world, represent a source of chemical and plastic pollution releasing thousands of toxic compounds and microfibers of cellulose acetate (CA). Besides the correct waste management, the recovery of CA from cigarette filters is a way to cushion their negative effects on the environment. Thus far, recycling strategies have been limited to industrial applications, while not many solutions have designed for water remediation. This work describes a strategy to valorize this harmful waste and to reverse its environmental impact, proposing a simple and effective procedure of reclamation of CA and its reuse to prepare a composite sorbent for the treatment of polluted water. The first step entails the washing of filters with hot water (T = 90 °C) and hot ethanol (T = 58-68 °C) to remove the impurities produced during cigarette burning, as verified by means of UV and attenuated total reflection-Fourier-transform infrared (ATR-FTIR) spectroscopy, thermal gravimetric analysis (TGA), and differential scanning calorimetry (DSC). The second step involves the use of the regenerated CA to prepare porous cylinder-shaped cryogels (15 mm × 10 mm) whose sorption properties are enhanced by the combination with AC (15 % w/w). The synthesis takes advantage of the sol-gel transition of the polymer dispersion (5 % w/V) in a solution acetone/water 5 mM in NH