TiO₂ nanotubes immobilized on polyurethane foam as a floating photocatalyst for water treatment

We investigated the photocatalytic activity of TiO₂ nanoparticles (TiO₂-NPs) and TiO₂ nanotubes (TiO₂-NTs) supported on a floating polyurethane (PU) foam for removing Bisphenol A (BPA) as a model pollutant. We fabricated TiO₂-NPs by the sol-gel method and TiO₂-NTs by the ultrasound-assisted hydrothermal method. Subsequently, the photocatalysts were immobilized onto the PU foam through the wet chemical deposition process. The synthesized photocatalysts were characterized by contact angle, SEM-EDS, TEM, XRD, DRS, and BET analyses. TiO₂-NPs and TiO₂-NTs were successfully deposited onto the PU foam, creating floating photocatalysts denoted as TiO₂-NPs@PU and TiO₂-NTs@PU. Our findings indicated that the nanotubular structure of floating TiO₂ photocatalysts enhanced the removal efficiency of BPA relative to the nanoparticles, resulting in the complete removal of the pollutant over 180 min of simulated sunlight irradiation. TiO₂-NTs@PU was also stable after five reuse cycles. Moreover, h+ was the main scavenging reactive species during the photocatalysis of BPA with TiO₂-NTs@PU.