In situ growth of TiO2 and its immobilization on PVDF films for the adsorption and photocatalytic degradation of dye

Abstract

Organic pollutants, such as dyes, contaminated water bodies seriously. Suitable materials and efficient technologies for degrading pollutants needed to be explored to protect the environment and human health. In this investigation, PVDF(PAA-g-β-CD)@TiO2 hybrid film was prepared by a combination of “in situ hydrothermal-vapor induction” under mild conditions. The distribution, particle size, and interaction with the film surface for TiO2 were investigated by XRD, XPS, SEM, and EDS. The TiO2 nanoparticles were firmly immobilized and uniformly distributed on the hybrid film surface. Poly (acrylic acid) (PAA) and β-cyclodextrin (β-CD) on the film matrix were connected by the chemical bond, which provided stable nucleation and growth sites for TiO2 while inhibiting photogenerated electron-hole recombination and significantly enhancing the adsorption ability. Furthermore, the multiple interaction forces (hydrogen bonding, coordination, and hydrophilic-hydrophilic interactions) between the film matrix and the TiO2 were evaluated by simulated geometries and theoretical calculations. The multiple interactions reduced the band gap (Eg) while endowing the hybrid photocatalytic film with excellent degradation efficacy (η), stability, and recycling properties. Finally, the η of methylene blue (MB) reached 97.34 % within 120 min and remained above 90 % even after 8 reuses. It was believed that PVDF(PAA-g-β-CD)@TiO2 film provided an approach for the mild preparation of polymer/TiO2 hybrid film with high catalytic activity and optimization of photocatalytic properties.