Structural and Performance Optimization of Polyethersulfone Membranes with Silane Coupling Agent Coated ZnO Nanoparticles for Removal of Congo Red Dye from Wastewater

Abstract

The current work introduces novel nanocomposite membranes fabricated via incorporating silane-functionalized zinc oxide nanoparticles within a polyethersulfone (PES) matrix. The membranes were synthesised via the classical phase inversion technique and bulk modified with a range of ZnO nanoparticle content from 0 to 2.5 wt.%. Comprehensive analytical techniques, including Fourier-transform infrared spectroscopy, energy-dispersive X-ray spectroscopy , field emission scanning electron microscopy , contact angle measurements and evaluations of pore size and porosity, were harnessed to identify the modification impact on membrane structure and surface characteristics. Results showed that ZnO nanoparticle content has notably influenced the morphology and physicochemical characteristics of the PES membranes. Compared to the neat PES membranes, the modified membranes had a slightly denser top surface and cross-sectional structure. Membrane wetting was remarkably improved as a reduction in contact angle from 73° to 43° was achieved. Nonetheless, the nanoadditive content was critical for membrane surface characteristics by diminishing average pore size, enhancing porosity and dye rejection efficiency, where 94.4% removal of Congo red was recorded. Furthermore, pure water flux witnesses a substantial change from 29.9 to 124.2 L/m²·h, indicating enhanced permeability. Obtained findings underscore the futuristic potential of silane-functionalized ZnO nanoparticles to comprehensively optimize the structural integrity, hydrophilicity and separation performance of PES membranes, endowing a promising approach for efficient treatment of textile wastewater streams.