Preparation of the ECTFE/SiO₂ Hybrid Membrane and Its Application in Membrane Condensation

As a new separation technology, membrane condensation requires simple equipment and mild operating conditions and has wide application potential and value in the process of water vapor recovery and chemical concentration and recovery. In this paper, we have proposed a new application process to incorporate nano-SiO2 into ECTFE membranes and apply them in the membrane condensation process. The fabrication of ethylene-chlorotrifluoroethylene copolymer (ECTFE)/SiO2 hybrid membranes is performed by incorporating hydrophobic nano-SiO2 during ECTFE membrane preparation, with varying ECTFE/SiO2 compositions achieved through SiO2 dosage adjustments. It can be found that SiO2 can change the structure of membrane during the process; hence, the impact of SiO2 removal after membrane formation on membrane performance was evaluated. SiO2 removal was conducted using a 1 mol/L hot alkali solution with continuous agitation for 24 h. A maximum water recovery rate of 24% (adequate for industrial water self-sufficiency) was attained at 2 wt % SiO2. Compared with the original membrane, the addition of hydrophobic nano-SiO2 significantly enhances the condensation performance of the ECTFE membrane.