Visible light driven photocatalytic coating of PAA plasma-grafted PVDF membrane by TiO2 doped with lanthanum recovered from waste fluorescent powder

In this study, the PDVF membranes were fabricated with a La-doped TiO2 (La-TiO2) photocatalytic coating in which La element was recovered from the waste fluorescent powder. The process of La element recovery was investigated under different conditions with different acid concentrations. La-TiO2 photocatalysts were facilely synthesized by the solvothermal method at 80°C followed by thermal sintering at 400°C. The La-TiO2 photocatalytic membrane fabrication was carried out by dip-coating the polyacrylic acid (PAA) plasma-grafted PVDF membrane into the suspension La-TiO2. The waste fluorescent powder was characterized by X-Ray Photoelectron Spectroscopy (XPS) and Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) after dissolving in the aqua regia. The La-TiO2 photocatalysts were characterized by Fourier-Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), UV–Vis diffuse reflectance spectroscopy (DRS), and Scanning Electron Microscopy (SEM). The La-TiO2 coated PVDF membrane was used to study the filtration and visible light driven photocatalytic degradation of Reactive Blue 5 solution. The experimental results showed that La-TiO2 possesses high photocatalytic activity (efficiency of 100% after 6-h irradiation), and the best membrane (La-TiO2/PAA/PVDF) performance (efficiency of 87%) with the water contact angle of 11.4⁰ was achieved. Thereby, it showed that the La-TiO2 photocatalytic membranes were successfully fabricated with antifouling, self-cleaning properties.