Bandgap tuning of TiO2 by Cu nanoparticles applied in photocatalytic antifouling-coated PES membranes through PAA-plasma grafted adhesive layer

Abstract

This study developed an antifouling coating for polyethersulfone (PES) membranes by tuning the bandgap of TiO2 with Cu nanoparticles (NPs) via a polyacrylic acid (PAA)-plasma-grafted intermediate layer. Cu NPs were synthesized at different molar ratios and precipitated onto TiO2 using the sol-gel method. The resulting Cu@TiO2 photocatalysts were characterized using various techniques, showing reduced bandgap, particle size range of 100–200 nm, and generation of reactive free radicals under light irradiation. The 25% Cu@TiO2 photocatalyst displayed the highest catalytic efficiency for Acid Blue 260 (AB260) degradation, achieving 73% and 96% with and without H2O2, respectively. Photocatalytic membranes based on this catalyst achieved an AB260 degradation efficiency of 91% and remained stable over five cycles. Additionally, sodium alginate-fouled photocatalytic membranes fully recovered water permeability after undergoing photocatalytic degradation of foulants. The modified membrane displayed a higher surface roughness due to the presence of photocatalyst particles. This study demonstrates the potential application of Cu@TiO2/PAA/PES photocatalytic membranes for mitigating membrane fouling in practice.