Preparation of Nanofiltration Membrane Modified with Sawdust‐Derived Cellulose Nanocrystals for Removal of Nitrate from Drinking Water

Abstract

In this work, cellulose nanocrystals (CNC) derived from sawdust were successfully incorporated into a nanofiltration membrane produced by the interfacial polymerization of piperazine (PIP) and trimesoyl chloride (TMC). The characteristics of unmodified and CNC‐modified membranes were investigated using scanning electron microscopy (SEM), Atomic Force Microscopy (AFM), zeta potential measurement, X‐ray photoelectron spectroscopy (XPS), and contact angle measurement. The performance of the membranes in terms of nitrate removal and water flux was investigated using 60 mg/L of potassium nitrate solution in a dead‐end test cell. The characteristics of the modified membrane revealed a more nodular structure, higher roughness, increased negative surface charge, and higher hydrophilicity than the pristine membrane, leading to nitrate rejection of 94%. In addition, the membrane gave an average water flux of 7.2 ± 1.8 L/m2/h/bar. This work implies that nanofiltration, a relatively low‐pressure process compared to reverse osmosis, can be used for improved nitrate removal from drinking water using an NF membrane modified with saw-dust‐derived cellulose nanocrystals.