疏水SiO2填充PDMS膜分离水中乙酸正丁酯的性能

以聚偏氟乙烯（PVDF）为支撑层，选用疏水性纳米SiO₂粉体作为改性剂，制备出聚二甲基硅氧烷（PDMS）复合膜材料，并用于乙酸正丁酯/水溶液的渗透汽化分离。采用SEM、FTIR、XRD、拉伸实验、接触角及正电子湮没寿命谱测定等对膜材料物理化学性能进行了表征，考察了膜材料的溶胀行为及渗透汽化性能。结果表明，SiO₂在PDMS膜中分散均匀，且没有发生化学作用，并提高了膜材料的机械强度和疏水性。随着SiO₂添加量增加，膜在乙酸正丁酯溶液中的溶胀度先升后降，渗透通量呈下降趋势，而分离因子先增大后减小。当SiO₂添加量为4%（质量）时，随进料浓度的增加，渗透通量增大，分离因子先增大后减小；随着温度升高，渗透通量增大，分离因子减小；渗透通量和分离因子最大值分别为240 g·m^-2·h^-1和542。

Separation of n-butyl acetate from aqueous solution using PDMS membrane filled with hydrophobic SiO2

The modified polydimethysiloxane (PDMS) hybrid membranes with hydrophobic nano SiO₂ as filler and using PVDF film as support layer were prepared for pervaporation of n-butyl acetate from aqueous solution. The physciochemical properties of membranes were characterized by SEM, FTIR, XRD, tensile testing, contact angle and positron annihilation lifetime spectroscopy(PALS). The effects of the loading of SiO₂, feed concentration, feed temperature on swelling behavior and pervaporation performance were studied. The results indicated that SiO₂ particles dispersed uniformly in the membrane material and no chemical change occurred between SiO₂ and PDMS polymer chain. The mechanical strength and hydrophobic properties of the filled film were obviously improved by incorporation of SiO₂. With the increase of SiO₂ content, the adsorption capacity of n-butyl acetate increased and then decreased, while the permeation flux decreased and the separation factor increased initially and then decreased. When SiO₂ content was 4%(mass), the permeation flux increased while the separation factor increased initially and then decreased with the rise of the feed concentration. The permeation flux increased with increase of the feed temperature, however, the separation factor decreased. The maximum values of the permeation flux and the separation factor were 240 g·m^-2·h^-1 and 542 respectively.