Novel CA/PVDF nanofiber supports strategically designed via coaxial electrospinning for high performance thin-film composite forward osmosis membranes for desalination

This study introduces a novel electrospun nanofiber mat fabricated via coaxial electrospinning as a support for high performance thin-film composite (TFC) forward osmosis (FO) membrane. This method produces a dual layer composite nanofiber support consisted of a polyvinylidene fluoride (PVDF) core layer and a cellulose acetate (CA) sheath layer, which provide mechanical stability and hydrophilicity, respectively. The CA sheath layer aims to cover the hydrophobic core layer and improve its hydrophilicity. The TFC FO membrane with coaxial electrospun CA/PVDF support layer not only showed high improvement in water flux due to improved hydrophilicity, but also exhibited comparable mechanical strength with pure PVDF nanofiber support. After FO operation using 0.5 M NaCl as draw solution and deionized water as feed solution, the coaxial electrospun CA/PVDF composite based TFC-FO membrane achieved the following: water flux of 31.2 L m(-2)h(-1), remarkably lower specific reverse salt flux of 0.03 g L-1, and low structural parameter of 190 mu m. Coaxial electrospinning is therefore a promising approach to fabricate high performance FO membrane whose support exhibits high porosity, mechanical stability, and hydrophilicity.