Gold-modified hierarchical ZnO Cellulose flower-like multifunctional membrane for enhanced wastewater treatment: Multifunctional oil/water separation, solar-powered catalytic dye degradation, and antibacterial applications

In this study, we develop an innovative composite membrane composed of cellulose nanofiber (CNF), polydimethylsiloxane (PDMS), and flower-like zinc oxide (F-ZnO) nanostructures, further functionalized with gold nanoparticles (AuNPs). This multifunctional membrane demonstrates remarkable antibacterial properties, effective photocatalytic degradation of organic dyes, and superior capabilities for oil/water separation. The distinctive flower-like morphology of the ZnO, combined with the presence of AuNPs, significantly boosts photocatalytic efficiency under ultraviolet (UV) light exposure, while also promoting superhydrophobicity and oleophilicity on the membrane's surface. The antibacterial efficacy of this membrane is notably enhanced against a wide range of pathogens. X-ray diffraction (XRD) confirmed the crystalline structures of cellulose and ZnO, while X-ray photoelectron spectroscopy (XPS) provided insights into the chemical states involved. The CNF/F-ZnO@Au composite achieved superior dye adsorption (40 mg/g for methylene blue) and photocatalytic degradation rates (97 % for methylene blue and 95 % for rhodamine B). The membrane also demonstrated exceptional oil/water separation capabilities with 90 % efficiency and a flux exceeding 70 L/(m²·h), attributed to superhydrophobic properties enhanced by the flower-like ZnO structure. These findings underscore the significant potential of this membrane for practical applications in wastewater treatment, effectively addressing challenges associated with pollution and resource recovery, while also promoting a novel candidate for multifunctional membranes.