Pushing the limits of high performance dual-layer hollow fiber fabricated via I²PS process in dehydration of ethanol

The immiscibility induced phase separation (I²PS) process was introduced as a novel method to fabricate hollow fibers with exceptionally high water permeance and reasonably high water/ethanol selectivity in dehydration of ethanol by pervaporation. As a continuation of the previous work, this study discloses the mechanisms to enhance the performance of hollow fibers spun via I²PS by elucidating the material selection at the inner-layer. Moreover, it revealed the methods to reduce mass-transport resistance by enhancing surface porosity for both inner and outer surfaces to further improve the permeation flux of the membranes. The continuous performance test demonstrates that the fibers spun from the I²PS possess a stable dehydration performance throughout the monitored period of 300 h. A comparison with pervaporation membranes in the literatures verifies the superiority of the membranes spun via I²PS process with the highest water permeation flux of 9.5 kg/m² h and the permeate water purity of 95.8 wt % at 80°C.