Improving Photocatalytic Performance and Recyclability by Development of Er-Doped and Er/Pr-Codoped TiO2/Poly(vinylidene difluoride)–Trifluoroethylene Composite Membranes

Photocatalysis has become an attractive process to remove contaminants from aquatic environments, with TiO 2 being the most widely used photocatalyst. In spite of the advantages of the process, two main problems still have to be overcome: reutilization/recycling of TiO 2 nanoparticles, which is a time-consuming and expensive process, and the fast recombination rate of the electron–hole pairs. This work reports on the photocatalytic activity of rare earth metal doped (erbium, Er) and codoped (erbium and praseodymium, Er/Pr) TiO 2 nanoparticles immobilized in a poly(vinylidene difluoride)–trifluoroethylene (PVDF–TrFE) copolymer membrane as a suitable strategy to overcome the aforementioned limitations. It is shown that doped and codoped nanoparticles were successfully immobilized into the PVDF–TrFE membranes, with a controllable degree of porosity. A high surface area (273 m 2 /g) was attained for these nanoparticles. The low band gap (2.63 eV) of these TiO 2 -modified nanoparticles, coupled with a highly porous structure (∼75%) of the membrane microstructure, synergistically envisages the best photocatalytic performance by degrading 98% of a solution of methylene blue after 100 min of exposure to UV.