Supported flat sheet nanocomposite polyvinylidenefluoride (PVDF) membranes embedded with hydrophilic TiO₂, hydrophobic TiO₂, or the combination of them were fabricated via phase inversion process. The membranes were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, atomic force spectroscopy, and the measurement of water contact angle and liquid entry pressure of water and subjected to tests on vacuum membrane distillation (VMD) performance. Addition of appropriate amounts of either hydrophilic or hydrophobic NPs was found to enhance VMD flux but hydrophilic NPs caused significant decrease of liquid entrance pressure of water (LEPw₎ while hydrophobic particles did not show significant impacts on LEP_w. Addition of both hydrophilic and hydrophobic NPs demonstrated synergistic effects in terms of both enhanced flux and LEP_w due to their different but complimentary effects on membrane structures. At feed temperature of 27.5 °C, the VMD pure water permeate flux of the composite membrane embedded with 5 wt% hydrophilic TiO₂ NPs and 2 wt% of hydrophobic TiO₂ NPs (total 7 wt% NPs) was 4.26 kg/m²h with a LEP_w of 28 psi, while those of neat PVDF membrane, the membrane embedded with 7 wt% of hydrophilic NP, and the membrane with 7 wt% hydrophobic nanoparticles were 0.335, 3.57, and 1.25 kg/m² h, respectively, and the LEPw of these membranes were 51, 24 and 47 psi, respectively. It is noted that at 5 wt% addition, the flux of M-L5 (hydrophilic NPs) is 3 times higher than the M-B5 (hydrophobic NPs). Furthermore, by adding another 2 wt% of NPs, flux increment by M-L5-B2 (hydrophobic NPs) is 3.5 times higher than M-L7 (hydrophilic NPs). Therefore, in both the effects combined, the highest flux was achieved by M-L5-B2 indicating synergistic effect of hydrophilic and hydrophobic NPs on the membrane flux. The salt rejection of above 99% could be maintained for 3 h by the membrane in which both hydrophilic and hydrophobic NPs were loaded. Numerical analyses of heat and mass transfer were also carried out to study the impact of hydrophilic and hydrophobic NPs on membrane characteristics.

通过相转化工艺制备了嵌有亲水性TiO ₂，疏水性TiO ₂或它们的组合的支撑平板纳米复合聚偏氟乙烯（PVDF）膜。通过扫描电子显微镜，能量色散X射线光谱，原子力光谱以及水的水接触角和液体进入压力的测量来表征膜，并进行真空膜蒸馏（VMD）性能的测试。发现添加适量的亲水性或疏水性NP可增强VMD通量，但是亲水性NPs导致水（LEPw _）的液体入口压力显着降低，而疏水性颗粒对LEPw没有显着影响_。由于它们对膜结构的不同但互补的作用，亲水性和疏水性NP的添加在通量和LEP _w方面均表现出协同作用。在进料温度为27.5°C时，嵌入5 wt％亲水TiO ₂ NP和2 wt％疏水TiO ₂ NP（共7 wt％NP）的复合膜的VMD纯水渗透通量为4.26 kg / m ² h LEP _w为28 psi，而纯PVDF膜，嵌入7 wt％亲水性NP的膜和7 wt％疏水性纳米颗粒的膜分别为0.335、3.57和1.25 kg / m ^2。h，这些膜的LEPw分别为51、24和47 psi。注意，在添加5重量％时，M-L5（亲水性NP）的通量是M-B5（疏水性NP）的3倍。此外，通过添加另外2 wt％的NP，M-L5-B2（疏水性NP）的通量增量比M-L7（亲水性NP）高3.5倍。因此，在两种作用的组合中，M-L5-B2达到了最高的通量，表明亲水性和疏水性NP对膜通量具有协同作用。装有亲水性和疏水性NPs的膜可将盐去除率保持在99％以上3小时。还进行了传热和传质的数值分析，以研究亲水性和疏水性NP对膜特性的影响。