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.