Sodium dodecylbenzene sulfonate (SDBS) assisted interfacial polymerization on a macro-porous nanofibrous support layer to prepare high-performance forward osmosis membranes

Forward osmosis (FO) technology is attracting increasing attention for seawater desalination because of its simple operation, low energy consumption, and low membrane fouling tendency. A continuous, suspended, and defect-free polyamide (PA) layer was prepared by SDBS assisted interfacial polymerization (IP) process without collapsing into the macropores of PAN nanofibers. The thickness and roughness of the PA layer increased with increasing SDBS concentration in the m-phenylenediamine (MPD) aqueous solution. Thin-film composite (TFC) FO membranes were more hydrophilic and electronegative. The Jw (water flux) of the TFC FO membranes first increased and then decreased as the SDBS content increased from 0 to 0.5 wt%. However, Js (reverse salt flux) exhibited an opposite trend to that of Jw. PAN/0.1-TFC FO membrane provided the optimal FO performance (Jw of 52.5 ± 3.0 L·m⁻²·h⁻¹ and Js of 4.9 ± 0.7 g·m⁻²·h⁻¹) when 3 mol·L⁻¹ NaCl was served as the draw solution. It also possessed outstanding anti-fouling and long-term stability properties. In summary, SDBS assisted IP process is a cost-effective process that can be easily scaled up for manufacturing. This approach facilitates the fabrication of FO membranes with excellent performance, utilizing macroporous nanofibers as the support layer.