FEP Hollow Fiber Membrane and Its Membrane Distillation Process

Abstract

The influence of draw ratio on the structure and properties of poly(tetrafluoroethylene-cohexafluoropropylene)(FEP) hollow fiber membrane which was fabricated by melt-spinning stretching(MS) method was investigated in this article.The primary FEP hollow fiber membrane structure was compact while the porous structure occurs after stretching.Furthermore,the increase of membrane draw ratios induced the obvious increase of membrane porosity and the N2flux while the decrease of the liquid entrance pressure(LEP).Meanwhile,the FEP hollow fiber membrane was applied to the vacuum membrane distillation(VMD) process to compared with M-S PP hollow fiber membrane which was the commercial product.The results show that the hydrophobic properties,LEP and mechanical strength of FEP hollow fiber membrane was better than PP hollow fiber membrane.The strong and stable of hydrophobic properties enabled the FEP membrane unpenetrated,which kept the desalination rate maintain up to 99%.The larger inner diameter(about 0.74 mm) of FEP hollow fiber membrane induced the use of internal pressure VMD type which brought about the higher VMD flux when the feed temperature increased.