Photo-cured fabrication of PDMS hollow fiber membrane for the pervaporative separation of 1-butanol from water

Polydimethylsiloxane (PDMS) is the benchmark pervaporation (PV) material, and its hollow fiber (HF) membrane is generally fabricated by thermal curing, which is energy-intensive and hard to be controlled. For the first time, a continuous and controllable photo-curing system for the fabrication of hydrophobic PDMS HF membrane is proposed. In this process, the uncoated PVDF HF membrane firstly exits from the feed roll, and enters into the tank filled with photo-cured PDMS solution. After being coated by PDMS, the new liquid layer uninterruptedly enters into the UV irradiation module and realizes the photo-curing reaction. Finally, the cured PDMS HF membrane moves into the take-up roll for collection. Due to this technology firstly being assessed, a series of operation parameters are optimized, including 126, 507 g mol−1 of the PDMS molecular weight, 12 wt% of PDMS concentration in its coating solution, 20.1 mW cm−2 of the irradiation intensity, 0.86 m min−1 of the rotation speed of roll and 1 time of the number of dip-coating. Under these parameters, the prepared PDMS HF membrane achieves an outstanding separation factor of 18.2 with a total flux of 1821 g m−2 h−1 for PV separation of 1-butanol. Our study has proven the feasibility of photo-cured fabrication of PDMS HF membranes for 1-butanol pervaporation.