Enhancement of desalination performance of thin-film nanocomposite membrane by cellulose nanofibers

Abstract

The incorporation of nanoparticles in a polymer membrane has been recognised as an effective strategy to improve the membrane performance in water processing. However, the leaching of nanoparticles from the membrane is potentially a concern as it may lead to the change of membrane properties and contamination of treated water. In this work, 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-oxidized cellulose nanofibers (CNFs) were for the first time incorporated into the polyamide layer of thin film composite (TFC) reverse osmosis (RO) membrane during interfacial polymerization to improve its membrane performance. CNFs are made from renewable and sustainable resources and they are non-toxic and environmentally friendly. The optimal loading of CNFs within the TFC membrane enhanced the permeance of the fabricated membranes by more than 50% (29.8 L m−2 h−1 at operating pressure of 1.5 MPa), whilst retaining high NaCl rejection at 96.2%. Chlorine stability test results indicated that the nanocomposite membranes showed better chlorine resistance performance than bare TFC membranes. This work successfully demonstrated the potential use of CNFs as a low cost and non-toxic filler to improve the performance of RO membranes for water desalination.