Self-Cleaning and Photodegradable PVDF-g-IL Dye Wastewater Separation Membranes Modified with Dopamine-Coated TiO₂ Core–Shell Particles

Abstract

In the present work, self-cleaning membranes of ionic liquid-grafted poly(vinylidene fluoride) (PVDF) polydopamine-coated TiO 2 were prepared through a nonsolvent-induced phase separation method. PDA facilitates the uniform dispersion of TiO 2 nanoparticles in PVDF substrates; meanwhile, TiO 2 @PDA core−shell particles and the hydrophilic IL improve the hydrophilicity of PVDF membranes and contribute to the increased average pore size and porosity, significantly improving the pure water permeation flux and dye wastewater flux (the water flux increased to 385.9 Lm −2 h −1 ). In addition, the combined effect of the positively charged IL and the strongly viscous PDA shell layer enhanced the retention and adsorption of dyes so that the retention and adsorption rates of both anionic and cationic dyes were close to 100%. Notably, the hydrophilic PDA allowed more TiO 2 to migrate to the membrane surface during the phase transition; on the other hand, dopamine could promote photodegradation. Therefore, the combined two factors for TiO 2 @PDA were beneficial to the ultraviolet-catalytic (UV-catalytic) degradation of dyes on the surface of the membrane, leading to >80% degradation rates of various dyes. Thus, the high-efficiency and easy-to-operate wastewater treatment technology provides attractive potential for dye removal and resolution of membrane contamination.

Synthesis of the Ag2S/PANI@PES Composite Membrane and Its Antipollution Properties

“…The photocatalytic membrane constructed through the integration of photocatalytic and membrane separation technology offers an efficacious resolution for addressing water contamination. , Photocatalysis, an advanced oxidation method, is capable of efficiently decomposing various organic pollutants, while the generated free radicals serve as an additional antibacterial . Semiconducting materials such as TiO 2 , , ZnO, CuS, and Ag 2 S have been applied in the synthesis of photocatalytic membranes. Among them, Ag 2 S is favored in the field of photocatalytic applications due to its excellent physicochemical properties and narrow band gap ( E g = 0.92 eV), alongside the strong antibacterial properties of silver ions, making it an optimal candidate for modifying membranes.…”