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 TiO2 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 TiO2 nanoparticles, which is a time-consuming and expensive process, and the fast recombination rate of the electronhole pairs. This work reports on the photocatalytic activity of rare earth metal doped (erbium, Er) and codoped (erbium and praseodymium, Er/Pr) TiO2 nanoparticles immobilized in a poly(vinylidene difluoride)trifluoroethylene (PVDFTrFE) copolymer membrane as a suitable strategy to overcome the aforementioned limitations. It is shown that doped and codoped nanoparticles were successfully immobilized into the PVDFTrFE 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 TiO2-modified nanoparticles, coupled with a highly porous structure (similar to 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.