Fabrication and characterization of ECTFE hollow fiber membranes via low-temperature thermally induced phase separation (L-TIPS)

Abstract Poly (ethylene chlorotrifluoroethylene) (ECTFE) hollow fiber membranes were fabricated by using low-temperature thermally induced phase separation (L-TIPS) method with the addition of composite powder which composed of a variety of soluble and insoluble microparticles. The formation mechanism of membrane structure was evaluated by a thermodynamic phase diagram of the dope solution with different ECTFE concentration. The influence of composite powder addition on the morphology, structure and performance of membranes was studied. It could be seen that ECTFE hollow fiber membranes prepared with composite powder had thinner dense skin layer, bicontinuous microporous structure, and presented superior porosity, permeability and mechanical properties. The salt rejection rate achieved 98.8% with permeate flux of 10.8 L m−2 h−1 in submerged vacuum membrane distillation (SVMD) experiment. Furthermore, the membranes exhibited well thermal and chemical resistance properties in harsh treatments.