Preparation of high-flux polyethylene hollow fiber microfiltration membranes with multiple pore structure through the combination technology of braided tube reinforcement and TIPS method

[Display omitted] •The reinforced PE hollow fiber membranes with high flux were prepared successfully.•The reinforced PE hollow fiber membranes obtained the multiple pore structure.•The reinforced PE hollow fiber membranes could achieve continuous preparation. Our team proposed the continuous preparation of the reinforced polyethylene (PE) hollow fiber microfiltration (MF) membranes based on the combination technology of braided tube reinforcement and thermally induced phase separation (TIPS) method. In this work, to improve the permeability and reduce the flux attenuation, we selected PE as the membrane-forming polymer, polyethylene glycol (PEG) and sodium chloride (NaCl) as the composite pore-forming agents to optimize the membrane-forming composition. In particular, the effect of NaCl contents on the permeation of the reinforced PE hollow fiber membranes was studied in detail. The reinforced PE hollow fiber MF membranes obtained the multiple pore structure containing small pores, large pores and cavity structure. The small pores were formed by PEG and white oil. The large pores and the cavity structure were formed by the discreted and agglomerated NaCl, respectively. The cavity structure provided the connectivity gaps for the small pores and forming an internal highly connected pathways, which could reduce the transmembrane resistance. Thus, the flux improved obviously with the increasing NaCl contents. When the NaCl content was 30 wt%, the pure water flux of the reinforced PE hollow fiber MF membranes could reach 1606.0 L·m−2 h−1 after pre-pressuring for 30 min. In addition, the reinforced PE hollow fiber MF membranes exhibited excellent tensile strength with 170.0 MPa and good corrosion resistance, which showed a great application potential in harsh environments. In particular, this method provides a new idea for the continuous preparation of the reinforced PE hollow fiber MF membranes.