Abstract

Membrane surface functionalization has shown great potential in improving the removal of organic pollutants from water by nanofiltration (NF). However, conventional surface modification methods rely on hazardous chemical solutions and produce large amounts of wastewater, which is contrary to the original purpose of wastewater remediation and the current high demand for environmental sustainability. Herein, we demonstrate a solvent-free and scalable method enabled by an emerging aerosol-assisted plasma deposition process for surface functionalization of NF membranes to improve the removal of organic pollutants from water. We first investigate the physicochemical properties of the aerosol-assisted plasma deposited (3-aminopropyl)triethoxysilane (AAPD-APTES) and 2-hydroxyethyl methacrylate (AAPD-HEMA) coatings on commercial NF270 membranes by different surface characterization techniques. Then, we examine the associated membranes' performance in removing conventional organic pollutants (phenol) and emerging micropollutants (diuron). Compared to the untreated NF270 membranes (2.9% for phenol and 22.0% for diuron), AAPD-APTES-modified NF270 membranes have the highest rejection efficiency toward both phenol (68.5%) and diuron (49.1%), whereas AAPD-HEMA coated membranes show good selectivity behavior with a high rejection efficiency for diuron (43.6%) but a relatively low efficiency for phenol (6.2%). Both plasma polymer-coated membranes are effective in removing organic contaminants mainly due to the plasma-produced dense surface coatings. Overall, this study offers a comprehensive eco-friendly and scalable strategy for NF membrane surface functionalization, which can not only improve the NF performance in wastewater remediation but also reduce the production of wastewater in the surface functionalization process.