Thin-film composite membrane based on 3D-printing support layer to minimize internal concentration polarization for efficient forward osmosis

Forward osmosis (FO) technology, characterized by high energy efficiency and low fouling propensity, holds considerable potential in desalination and wastewater reclamation. Nevertheless, the tortuous microporous structure of conventional support layers induces severe internal concentration polarization (ICP), limiting performance enhancement and further application of FO membranes. Here, we report the fabrication of 3D-printing support layers featuring through-pore structures, followed by integrating PES-COOH separation layers to develop a novel PES-COOH-TFC FO membrane. The through-pore architecture of 3D-printing support layers endows PES-COOH-TFC FO membranes with an ultra-low structural parameter, effectively mitigating the detrimental influence of ICP on membrane permeability. Moreover, surface segregation within the ultrathin PES-COOH separation layer promotes carboxyl enrichment on the membrane surface, ensuring superior rejection for the salt solutes. The optimal PES-COOH-TFC FO membrane achieved a water flux of 9.6 L m −2 h −1 and a reverse salt flux of 6.3 mmol m −2 h −1 when assessed using 2 M NaCl draw solution, corresponding to a superior reverse flux selectivity of 1523.8 ± 132.6 L mol −1 . This study transcends conventional structural design by introducing a strategy that leverages high-precision 3D printing technology to optimize FO membrane performance, offering a novel paradigm for the fabrication of advanced separation membranes.