Polyamide Nanofiltration Membranes Incorporated with Cellulose Nanocrystals for Enhanced Water Flux and Chlorine Resistance

Nanofiltration membranes (NFMs) with a high water permeation flux and salt rejection are extremely desirable due to their low energy consumption and superior separation efficiency in practical applications. Herein, cellulose nanocrystals (CNCs) prepared by the sulfuric acid hydrolysis of microcrystalline cellulose were directly incorporated in the aqueous solution of piperazine for fabricating thin film nanocomposite (TFN) NFMs by interfacial polymerization. The as-fabricated TFN NFMs exhibit obviously rougher and more hydrophilic surfaces compared with those thin film composite membranes without CNCs, resulting in a drastic increase of water permeation flux (106.9 L.m(-2) h(-1)) while keeping a reasonable salt rejection to Na2SO4 (98.3%) and MgSO4 (96.1%). Moreover, the TFN NFMs maintain a relatively stable water permeation flux after exposure to NaClO solution, benefiting from the remarkable hydrophilicity of CNCs. This study conveys that those easy-to-prepare, acid base stabilized, organic nanofillers have a great potential to prepare TFN NFMs for water desalination and purification.