Evaluating the Impact of Cellulose Nanocrystals on the Performance of Polycarbonate Thin‐Film Nanocomposite Membranes for Treating Oily Wastewater

ABSTRACT A new type of thin‐film nanocomposite (TFN) membrane was synthesized by incorporating cellulose nanocrystals (CNCs) into a polyvinyl alcohol (PVA) top layer on a polycarbonate (PC) substrate via dip‐coating. The synthesized TFC and TFN membranes (PC/PVA TFC and PC/PVA‐CNC TFN membranes) were evaluated using contact angle measurement, field emission scanning electron microscopy (FE‐SEM), and atomic force microscopy (AFM). All membranes were applied in a cross‐flow filtration system for oily wastewater treatment. The results showed that the membranes' hydrophilicity increased significantly when 0.1 wt.% CNC was used. The water flux for the PC/PVA TFC membrane was measured at 19.5 L/m 2 ·h, while the flux for the PC/PVA‐CNC 0.05% TFN membrane was 34.7 L/m 2 h, demonstrating a substantial increase in permeability. FE‐SEM investigations revealed the existence of an active layer on both the PC/PVA TFC and PC/PVA‐CNC TFN membranes, with corresponding thicknesses of 235 and 170 nm, respectively. The total organic carbon (TOC) concentration for the PC/PVA TFC membrane was 30.2 mg/L, which decreased to 21.3 mg/L and 22.6 mg/L for the TFN‐CNC 0.05% and TFN‐CNC 0.1% membranes, respectively. This study highlights the potential of CNC‐enhanced TFN membranes to improve the performance and longevity of membrane filtration systems in treating oily wastewater, offering significant implications for environmental sustainability and industrial applications.