Fabrication and characterization of high-performance acetone-assisted polyamide thin-film composite membranes for fluoridated saline water treatment

Nanofiltration (NF) and reverse osmosis (RO) membrane show promising potential for treating fluoridated brackish water and wastewater. We assessed the water flux and rejection performance of a self-fabricated membrane with various acetone concentrations as co-solvent for the treatment of fluoridated brackish water. The membrane performance was studied at different pH and pressure levels using a crossflow RO test cell with a single fluoride feed solution, brackish water composition, and real seawater. The addition of acetone to the organic and aqueous solutions during interfacial polymerization reduced the solubility difference and formed a narrower miscibility zone, resulting in a thicker reaction zone and a multilayer polyamide structure with larger pores. The water flux performance improved as the acetone concentration rose, with just a minor loss in fluoride solute rejection. Additionally, the fluoride removal efficiency increased with pH increase as the membrane became highly negatively charged. The performance of acetone added membrane was compared with commercial RO/NF membranes under the same conditions, and the acetone-added membrane exhibited higher flux and rejection. This work illustrates the utility of an acetone-assisted membrane as a suitable stand for fluoride removal and brackish water treatment.