Selective-layer polysulfone membranes based on unfunctionalized and functionalized MoS2/polyamide nanocomposite for water desalination.

Abstract

Recently, reverse osmosis (RO) has become the most widely used process in membrane technology. It has aroused great interest in water desalination through membranes. According to recent studies, the surface properties of support layers in thin film membranes are crucial for improving reverse osmosis performance. Surface polymerization was used to produce the membranes in this work, with the polyamide acting as a selective layer on the polysulfone support film. Three membranes were produced with different proportions of molybdenum sulfide (MoS₂) nanopowder. The effectiveness of the membranes was improved by increasing water permeability while maintaining excellent salt retention. All membranes produced were tested using various characterization methods including scanning electron microscope, Brunauer-Emmett plate, and zeta potential. The water permeability of the polyamide membrane with PA-MoS₂ (0.015% w/v) was 29.79 L/m² h bar, more than the PA-MoS₂ membranes (0.005% w/v, 19.36 L/m² h) and PA-MoS₂ (0.01% w/v, 3.63 L/m² h bar). Under the same conditions, salt rejection of more than 96.0% for NaCl and 97.0% for MgSO₄ was also observed. According to the SEM, the 0.015% PA-MoS₂ membrane exhibited lower surface roughness, greater hydrophobicity, and a higher water contact angle. Due to the hydrophobic nature of MoS₂, these properties resulted in the lowest salt rejection.