Design and fabrication of TiO2/Nd polyurethane nanofibers based photoreactor: A continuous flow kinetics study for Estriol degradation and mechanism

Novel polyurethane (PU) nanofibers incorporated with the neodymium (Nd) doped TiO2 nanoparticles were fabricated by electrospinning process and employed for the photocatalytic degradation of the estriol (E3) hormone. Nanofibers possessed high porosity (0.47 μm) and uniform mesh-like structure while suitable incorporation of TiO2/Nd nanoparticles with increasing concentrations (5, 10, and 20 %) was obtained. The TiO2/Nd incorporated PU nanofiber photocatalytic activity under UV and visible light was evaluated using a continuous drip flow biofilm reactor. To establish sufficient adherence to the PU matrix necessary to maintain durability during crossflow reactor, the as-prepared nanofibers were thermally pressed on polyethylene terephthalate (PET) sheets to avoid any potential folding. The nanofibers performed better in UV than visible, with maximum degradation rates of ∼90.2 % and 30.4 %, respectively, at pH 7 in 120 min. The degradation performance of nanofibers increased with an increase in the number of layers and decreased with the E3 solution flow rate. The experimental data best fitted for the pseudo-first-order kinetic model with regression coefficient (R2) > 0.9. The highest degradation removal capacities were 2.436 and 0.847 mg/g under UV and visible light irradiation, respectively. The results showed that TiO2/Nd incorporated PU nanofibers exhibit a potential to degrade hormones from environmental water.