Preparation of Nano-TiO2/polyurethane membrane and study of its photocatalytic properties

Abstract To overcome the problem of separation and recovery of photocatalysts in water, modification of TiO 2 nanoparticles were incorporated into a polyurethane (PU) membrane to form a stable and reusable photocatalytic system. The nano-sized TiO 2 photocatalysts were employed to enhance the specific surface area, thereby improving photocatalytic performance. The polyurethane membrane was synthesized via the phase-inversion method using avocado seed oil as a bio-based source of hydroxyl (-OH) groups, which reacted with hexamethylene-1,6-diisocyanate (HDI) as a source of isocyanate (-NCO) groups. Characterization by XRD confirmed the formation of TiO₂ with a crystallite size of 11.5 nm and a 2θ value of 25.27°, while FTIR spectra identified characteristic –NH and –C=O (urethane carbonyl) groups, along with Ti–O and Ti–O–Ti vibrations, indicating the successful incorporation of TiO 2 within the polymer matrix. SEM analysis revealed a semi-globular morphology with well-dispersed TiO 2 particles. The photocatalytic activity of the TiO 2 /PU membrane was evaluated through the photodegradation of methyl orange as a model pollutant, achieving degradation efficiencies of 91.2% in both the first and second cycles, demonstrating excellent photocatalytic performance and reusability.