School of Energy and Environment , City University of Hong Kong , Tat Chee Avenue , Kowloon , Hong Kong Special Administrative Region , China.
Department of Environmental Engineering , Daegu University , 201 Daegudae-ro , Jillyang, Gyeongsan-si , Gyeongbuk 38453 , Republic of Korea.
Environ Sci Technol. 2019 May 7;53(9):4948-4958. doi: 10.1021/acs.est.8b07254. Epub 2019 Apr 23.
Electrospun nanofiber membranes (ENMs) have garnered increasing interest due to their controllable nanofiber structure and high void volume fraction properties in membrane distillation (MD). However, MD technology still faces limitations mainly due to low permeate flux and membrane wetting for feeds containing low surface tension compounds. Perfluorinated superhydrophobic membranes could be an alternative, but it has negative environmental impacts. Therefore, other low surface energy materials such as silica aerogel and polydimethylsiloxane (PDMS) have great relevancy in ENMs fabrication. Herein, we have reported the high flux and nonwettability of ENMs fabricated by electrospraying aerogel/polydimethylsiloxane (PDMS)/polyvinylidene fluoride (PVDF) over electrospinning polyvinylidene fluoride- co-hexafluoropropylene (PVDF-HFP) membrane (E-PH). Among various concentrations of aerogel, the 30% aerogel (E-M3-A30) dual layer membrane achieved highest superhydrophobicity (∼170° water contact angle), liquid entry pressure (LEP) of 129.5 ± 3.4 kPa, short water droplet bouncing performance (11.6 ms), low surface energy (4.18 ± 0.27 mN m) and high surface roughness ( R: 5.04 μm) with re-entrant structure. It also demonstrated nonwetting MD performance over a continuous 7 days operation of saline water (3.5% of NaCl), high antiwetting with harsh saline water containing 0.5 mM sodium dodecyl sulfate (SDS, 28.9 mN m), synthetic algal organic matter (AOM).
静电纺纳米纤维膜（ENMs）因其可控的纳米纤维结构和高空隙体积分数特性在膜蒸馏（MD）中受到越来越多的关注。然而，MD 技术仍然存在局限性，主要是由于进料中含有低表面张力化合物时渗透通量和膜润湿较低。全氟超疏水膜可能是一种替代方法，但它对环境有负面影响。因此，其他低表面能材料，如硅胶和气凝胶和聚二甲基硅氧烷（PDMS），在 ENMs 制造中具有重要意义。在此，我们通过静电纺丝聚偏氟乙烯-共六氟丙烯（PVDF-HFP）膜（E-PH）上的静电喷涂气凝胶/聚二甲基硅氧烷（PDMS）/聚偏氟乙烯（PVDF）报道了由静电纺丝制备的 ENMs 的高通量和非润湿性（E-PH）。在各种浓度的气凝胶中，30%气凝胶（E-M3-A30）双层膜实现了最高的超疏水性（~170°水接触角）、液体入口压力（LEP）为 129.5±3.4 kPa、短水滴反弹性能（11.6 ms）、低表面能（4.18±0.27 mN m）和高表面粗糙度（R：5.04 μm），具有倒凹结构。它还展示了在连续 7 天运行盐水（3.5%NaCl）、含有 0.5 mM 十二烷基硫酸钠（SDS，28.9 mN m）的苛刻盐水、合成藻类有机物（AOM）时的非润湿 MD 性能。
