Preparation and characterization of novel forward osmosis membrane incorporated with sulfonated carbon nanotubes

In this study, carbon nanotubes (CNTs) were modified with sulfonated groups and incorporated into the active layer of a forward osmosis (FO) membrane to achieve a desirable thin-film nanocomposite (TFN) FO membrane. Different concentrations of sulfonated carbon nanotubes (SCNTs) were added, and their impact on the FO membrane was also investigated, including the hydrophilicity, roughness, membrane morphology and FO performance. With the addition of SCNTs, the membrane surface got smoother and denser, and the hydrophilicity also improved significantly. Regarding FO performance, SCNTs-functionalized FO membranes exhibited higher water flux (J(w)) and lower reverse salt flux (J(s)). The optimal J(w) of 29.9 ± 1.6 LMH was achieved by using 1 M NaCl solution as the draw solution (DS) and deionized (DI) water as the feed solution (FS), almost 140% higher than the control (21.3 ± 2.1 LMH) and J(s) decreased to about 12%.