Controllable prepared PDMS/SiO2/PVDF membrane for the separation of gaseous peppermint aromatic water

One of the main challenges in oil–water separation of traditional Chinese medicines (TCM) is to obtain essential oils from the aromatic water of TCM. In this study, silicon dioxide/polyvinylidene fluoride (SiO 2 /PVDF) membranes were prepared using nonsolvent induce phase separation. Then polydimethylsiloxane (PDMS) was coated to obtain PDMS/SiO 2 /PVDF membranes. Separated essential oils and water from aromatic water in the gaseous state by vapor permeation membrane separation technology. The relationship between membrane structure and membrane separation effect was investigated. Response surface methodology was used to develop a quadratic model for the separation factor, membrane permeation separation index and membrane preparation process. The optimal process parameters for the membrane separation were 12.31% (mass) concentration of PVDF solution, 9.6% (mass) of N,N -dimethylacetamide in the solidification bath, and 0.2 g hydrophobic nano-SiO 2 incorporation, with a separation factor of 14.45, and a membrane flux of 1203.04 g·m –2 ·h –1 . Compared with the PDMS/PVDF membranes, the separation factor and membrane flux were increased by 68.59% and 3.46%, respectively. Compared with the SiO 2 /PVDF membranes, the separation factor and membrane flux were increased by 478% and 79.33%, respectively. Effectively mitigated the limitations of traditional polymer membrane material performance affected by the “trade-off” effect. Attenuated total internal reflection-Fourier transform infrared spectroscopy, contact angle, scanning electron microscopy and energy dispersive spectroscopy were used to characterize the PDMS/SiO 2 /PVDF membranes, and gas chromatography was used to characterize the permeate. In addition, the contents of L -menthol, L -menthone, menthyl acetate and limonene in the permeate, conformed to the European Pharmacopoeia standards . This study provided an effective preparation strategy of a feasible hydrophobic powder polymer membrane for the separation of essential oils from gaseous peppermint aromatic water.