One-pot preparation of a carboxylated nanocrystalline cellulose from oil palm fronds as hydrophilic additive for enhancement of membrane permeability and anti-fouling properties

Most polymeric membranes, including polyethersulfone (PES), are limited in their application due to their low water flux and high fouling characteristic. In this study, carboxylated nanocrystalline cellulose (C-NCC) embedded PES membrane was fabricated using the non-solvent induced phase inversion (NIPS) method to enhance the water permeability and anti-fouling properties of the PES membrane. Herein, we synthesized our C-NCC from oil palm fronds (OPFs) using a simple and time-efficient one-pot mixed acid hydrolysis method. The as-prepared C-NCCOPF exhibited a rod-like structure with dimensions of 121.03 ± 65.30 nm and 15.64 ± 5.42 nm in length and width, respectively. The degree of oxidation value of 0.21 was obtained, comparable to those C-NCC synthesized using the classical TEMPO or APS oxidation procedures. By incorporating C-NCCOPF nanorods into the PES matrix, the hydrophilicity, pore structure, mean pore size, porosity, and pure water flux of the modified membrane were significantly enhanced. The Hermia model and Bolton's combined fouling model were applied to investigate the anti-fouling properties of the fabricated membrane during the HA filtration at 1 bar operating pressure. The results demonstrated that the pristine PES membrane was susceptible to fouling which is likely related to the hydrophobic nature of the PES polymer. In contrast, it was discovered that incorporating the C-NCCOPF into the PES membrane could significantly reduce fouling and enhance membrane performance.