Fabrication and characterization of a novel hydrophobic polystyrene membrane using electroblowing technique for desalination by direct contact membrane distillation

In this work, a new hydrophobic membrane with nanofibrous structure was prepared from polystyrene using the electroblowing technique, for the first time, for desalination experiments. Using this technique, the injection rate for the dope solution increased up to 117 µL/min. This means faster and considerably higher fiber productivity as compared to the typical electrospinning. The membrane was treated via a hot-press post treatment. The new membrane was analyzed for the surface morphology and topography, and was then evaluated for desalination using DCMD process. The results for the new membrane compared to a commercial PTFE membrane with 0.22 µm pore size. Larger mean pore size (0.562 µm) was observed for the new membrane. However, the membrane porosity for the nanofibrous membrane was comparable with the PTFE one (~75%). The fabricated membrane was thinner and therefore it produced higher permeate flux. Both fabricated and commercial membranes showed ˃99% salt rejections for lower range of feed flow rate (≤0.48 L/m). Most importantly, the new membrane fabricated using a cheap and available polymer via a fast technique for DCMD desalination. The hot-pressed, nanofibrous membrane showed higher surface hydrophobicity (154.52°) than the commercial membrane (124.61°). The superhydrophobic state of the new membrane prevented the liquid encroachment into the membrane pores. This consequently improved not only the permeate flux, but also the average salt rejection. Overall, the new fabricated membrane showed a reasonable desalination performance.