Development of polyethersulfone/polylactic acid‐blended nanocellulose membranes for enhanced removal of methylene blue dye

Abstract

AbstractHerein, adsorptive polyethersulfone/polylactic acid (PES/PLA) blends membranes with systematic concentrations of cellulose nanofibers (CNFs) (0.5–2.5 wt%) were developed via a modified phase inversion process for the enhanced removal of cationic methylene blue (MB) dye. To the best of our knowledge, this is the first time that such adsorptive membranes have been produced for potential use in wastewater treatment. The fabricated membranes were characterized for surface and cross‐sectional morphology (scanning electron microscope), surface roughness (atomic force microscope), functionality (Fourier‐transform infrared spectroscopy), thermal stability (thermal gravimetric analysis), wettability (contact angle measurements), antifouling behavior (flux recovery studies), and dye adsorption and reusability (adsorption and desorption tests). CNF incorporated membranes showed improved wetting properties, with contact angle decreasing from 76° in the pristine membranes to 48° in 2.5 wt% PES/PLA membranes. The membrane bulk porosity increased from 60.3% to 79.23%, while the pure water flux increased from 210.8 to 399.12 Lm−2 h−1. At optimal conditions, CNF‐modified membranes removed >98% of MB compared with 8% removal by the pristine membranes. After five cycles of adsorption and desorption, the membrane with 2 wt% CNFs achieved over 70% dye removal showing excellent reusability properties. Adsorption followed pseudo‐second‐order and Freundlich models. The adsorption was attributed to electrostatic interactions between the negatively charged membrane surfaces and the positively charged dye molecules as well as through hydrogen bonding. Therefore, this work revealed that CNF‐modified PES/PLA membranes can be used as adsorbents for the enhanced removal of organic pollutants in water treatment applications.