| Summary: | 碩士 === 中原大學 === 化學工程研究所 === 105 === In this study, we prepared poly(vinylidene fluoride) (PVDF) membranes by vapor-induced phase separation (VIPS) process. Then, we modified the membranes using styrene and sulfobetaine methacrylate (SBMA) (PS-r-PSBMA) via reaction-induced self-deposition process, in which the polymerization and coating of styrene and SBMA on the membranes occur at the same time. The goal was to prepare superhydrophilic/superoleophobic membranes that can easily separate oil-in-water emulsions by gravity separation process.
The membranes were characterized by water and oil contact angle measurement, scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), fourier transform infrared spectroscopy (FT-IR). Oil-in-water emulsion separation was performed by filtration under low transmembrane pressure (0.5 atm), Karl Fischer method enabled to evaluate the composition of the permeate and of the retentate, and thus the separation efficiency of the membrane.
Different reaction parameters such as the reaction time, the monomer ratio and the solid content were varied in order to optimize the surface hydrophilicity of the membranes. The results showed that the reaction carried out for 5 hours, using a styrene/SBMA ratio of 40/60 and a total solid content of 5 wt% led to desirable hydrophilic property as the water contact angle was found to be 0˚ within 10 seconds after contact between the water droplet and the membrane. And oil contact angle under water was 140 ˚. Then, toluene, hexane, hexadecane, diesel and soybean oil were used to prepare oil-in water emulsions and separated by membrane filtration under low transmembrane pressure (0.5 atm). In addition, a separation efficiency higher than 99% was measured in both cases. Thus these membranes hold promise as potential materials for breaking of O/W emulsions.
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