Synthesis and Characterization of a Modified Silica/Cellulose Acetate Nanocomposite Ultrafiltration Membrane for Phenol Removal from Wastewater

Abstract

In addressing the critical environmental challenge of phenol pollution in water sources, this work studies phenol removal from wastewater using advanced ultrafiltration membranes. These membranes are enhanced with hydrophilic nanoparticles, specifically silica-based ones, to boost their efficiency and effectiveness. The process involves creating cellulose acetate (CA) mixed-matrix membranes, where silica nanoparticles are initially coated with a choline chloride-ethylene glycol deep eutectic solvent (DES). This composite is then incorporated into the CA membranes at varying concentrations of 0.25 %, 0.5 %, and 0.75 % by weight using phase inversion. The membranes are thoroughly examined for their structure and performance utilizing scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, contact angle measurements, pore size analysis, porosity assessment, and mechanical strength tests.Additionally, water flux and phenol removal performance tests were performed using a dead-end filtration setup at a pressure of 1 bar. Incorporating DES-modified nanofillers significantly enhances the membranes’ hydrophilicity and phenol removal efficiency. The internal structure exhibits a finger-like morphology with increased porosity and larger pore sizes. Notably, the membrane fabricated with 0.5 wt% modified nanoparticles showed the highest phenol removal (about 74 %) for 30 ppm aqueous phenol and water flux of 126.38 L m−2h−1. This indicates that using modified nanoparticles (DES-SiO2) in engineering ultrafiltration (UF) membranes results in an enhanced pore structure, improved chemical properties, and the effective removal of small molecules, including phenol.