Freestanding Ptfe Electrospun Tubular Membrane For Reverse Osmosis Brine Concentration By Vacuum Membrane Distillation

The desalination of highly concentrated brine wastewater is still a challenge in water treatment. In the present study, tubular polytetrafluoroethylene (PTFE) membranes were prepared by electrospinning and sintering method with the assistance of removable template. By increasing the membrane thickness, freestanding PTFE tubular membranes with sufficient strength and high liquid entry pressure value available in vacuum membrane distillation (VMD) were obtained. Their permeate flux and scaling behavior were further evaluated by VMD process for simulated reverse osmosis (RO) brine desalination. The results demonstrate that membrane scaling and permeate flux were highly related to the feed flowing conditions, especially in the saturation stage. The relationship of the salt crystallization mechanism, flowing disturbance conditions and VMD performance was further discussed. In proper flowing conditions, foulants mainly formed in the solution bulk and can be cleaned easily by the flushing of the feed flow. In four cycles of continuous concentration, the tubular membranes exhibit a steady performance of flux and rejection. These results shed light on the feasibility and prospect of the tubular electrospun membranes in high salinity brine desalination.