Cellulose nanocrystal-blended polyethersulfone membranes for enhanced removal of natural organic matter and alleviation of membrane fouling

To prevent membrane fouling caused by natural organic matter (NOM), cellulose nanocrystals (CNCs) were blended with inherently hydrophobic polyethersulfones (PES) by the phase inversion method to fabricate nanocomposite membranes. Characterization of the membrane surface morphology indicated that the CNC-containing nanocomposite membranes exhibited homogeneous surfaces. Compared to the neat PES membrane, the nanocomposite membranes had higher porosity and zeta potentials. The static contact angle and pure water flux of the nanocomposite membranes indicated an increase in hydrophilicity of the modified membranes. However, the porosity and permeability of the nanocomposite membranes decreased at 5.0 wt% CNC loading. The NOM removal and fouling experiments were performed using humic acids (HAs), bovine serum albumin (BSA) and sodium alginate (NaAlg) as surface water pollutants. The removal rates of hydrophobic HA and BSA were significantly increased by the developed membranes. The nanocomposite membranes exhibited enhanced anti-NOM fouling properties, increased cleaning efficiency and effective control of both reversible and irreversible fouling. This study provides insight into the utilization of high-performance nanocomposites for a wide range of water treatment applications.