Tailoring surface structures of PVDF hollow fiber membranes using triple-orifices spinneret in the TIPS process for membrane distillation

摘要

Membrane distillation(MD)is an emerging thermal driven membrane separation technology for desalting highly saline solutions.PVDF hollow fiber membrane has attracted much attention in MD due to its high hydrophobicity.However,PVDF hollow fiber membranes prepared using a blooming thermally induced phase separation(TIPS)usually show dense surface and sub-layer,which causes low permeability and drastically affects its application in MD with high efficiency.In this work,a new method was used to tailor the surface structure of PVDF hollow fiber membranes by extruding solvents at the outer surface of the extruded polymer solution using a triple-orifice spinneret in the TIPS process.