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

Abstract

In this study, the PDVF membranes were fabricated with a La-doped TiO 2 (La-TiO 2 ) 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-TiO 2 photocatalysts were facilely synthesized by the solvothermal method at 80°C followed by thermal sintering at 400°C. The La-TiO 2 photocatalytic membrane fabrication was carried out by dip-coating the polyacrylic acid (PAA) plasma-grafted PVDF membrane into the suspension La-TiO 2 . 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-TiO 2 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-TiO 2 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-TiO 2 possesses high photocatalytic activity (efficiency of 100% after 6-h irradiation), and the best membrane (La-TiO 2 /PAA/PVDF) performance (efficiency of 87%) with the water contact angle of 11.4⁰ was achieved. Thereby, it showed that the La-TiO 2 photocatalytic membranes were successfully fabricated with antifouling, self-cleaning properties.

Enhancing NO degradation in visible light through plasma-treated photocatalytic substrates featuring TiO₂@g-C₃N₄ Z-scheme structure

“…This decrease in contact angle is comparable to the findings observed in La-doped TiO 2 subjected to a cold radio frequency (RF) discharge plasma at low pressure. In the case of the PVDF membrane surface, the contact angle decreased from 121.1° to 9.2°, as measured using waste fluorescent powder [58].…”

Environment-friendly fluoride-free membranes from plasma-activated hydrophilic PES and alkylsilanes applied in MD: grafting optimization, surface properties, and performance

“…In this study, the oxygen plasma method with mild operating conditions at low pressure and the room temperature was chosen because it was just enough to activate the PES membrane surface without damaging the membrane's mechanical strength. [36][37][38][39] In addition, compared to chemical methods, this plasma method can be considered a green and highperformance method because of its short processing time, completely controlled conditions, and no generation of waste chemicals and waste solvents. Mechanistically, oxygen cold plasma will trigger the formation of positive or negative charges and reactive free radicals on the PES membrane surface.…”