Fabrication of novel hydrophobic electrospun nanofiber membrane using polybenzoxazine for membrane distillation application

In this study, a novel hydrophobic blend polyvinylidene fluoride (PVDF) nanofibrous membrane with polybenzoxazine (PBz) was fabricated by the electrospinning technique to apply in membrane distillation (MD) process. Accordingly, pristine PVDF and a fluoro containing benzoxazine monomer (Bz) was blended and then thermally treated for crosslinking the Bz. The membrane properties were determined in terms of contact angle, young module, thickness, and the membranes were characterized by scanning electron microscope and Fourier transform infrared spectroscopy. The water contact angle of membranes increased from ca. 102.8° for the pristine PVDF membrane to 132.7° post cured Bz blended membrane. Moreover, the mechanical properties of blended membranes enhanced, while obtaining smoother and physically more stable membranes compared to the pristine nanofibrous membrane. The optimum membranes were tested in a lab-scale vacuum assisted air gap membrane distillation system. Results showed that Bz blended and cured membranes exhibited higher rejections and permeate flux for reverse osmosis brine and boron solutions compared to the pristine membrane that demonstrate the promising potential of Bz blended membranes in MD applications.