Dong Zhe-Qin, Wang Bao-Juan, Ma Xiao-hua, Wei Yong-Ming, Xu Zhen-Liang
State Key Laboratory of Chemical Engineering, Membrane Science and Engineering R&D Lab, Chemical Engineering Research Center, Shanghai Key laboratory of Mutiphase Materials Chemical Engineering, East China University of Science and Technology (ECUST) , 130 Meilong Road, Shanghai 200237, China.
ACS Appl Mater Interfaces. 2015 Oct 14;7(40):22652-9. doi: 10.1021/acsami.5b07454. Epub 2015 Oct 2.
This study develops a novel type of electrospun nanofiber membranes (ENMs) with high permeability and robust superhydrophobicity for membrane distillation (MD) process by mimicking the unique unitary microstructures of ramee leaves. The superhydrophobic ENMs were fabricated by the eletrospinning of poly(vinyl alcohol) (PVA), followed by chemical cross-linking with glutaraldehyde and surface modification via low surface energy fluoroalkylsilane (FAS). The resultant FAS grafted PVA (F-PVA) nanofiber membranes were endowed with self-cleaning properties with water contact angles of 158° and sliding angles of 4° via the modification process, while retaining their high porosities and interconnected open structures. For the first time, the robust superhydrophobicity of the ENMs for MD was confirmed by testing the F-PVA nanofiber membranes under violent ultrasonic treatment and harsh chemical conditions. Furthermore, vacuum membrane distillation experiments illustrated that the F-PVA membranes presented a high and stable permeate flux of 25.2 kg/m2 h, 70% higher than those of the commercial PTFE membranes, with satisfied permeate conductivity (<5 μm/cm) during a continuous test of 16 h (3.5 wt % NaCl as the feed solution, and feed temperature and permeate pressure were set as 333 K and 9 kPa, respectively), suggesting their great potentials in myriad MD processes such as high salinity water desalination and volatile organiccompounds removal.
本研究通过模仿苎麻叶独特的单一微观结构，开发出一种具有高渗透性和强大超疏水性的新型电纺纳米纤维膜（ENMs），用于膜蒸馏（MD）过程。通过静电纺丝制备聚乙烯醇（PVA）超疏水ENMs，然后用戊二醛进行化学交联，并通过低表面能氟代烷基硅烷（FAS）进行表面改性。通过改性过程，所得的FAS接枝PVA（F-PVA）纳米纤维膜具有自清洁性能，水接触角为158°，滑动角为4°，同时保留了其高孔隙率和相互连通的开放结构。首次通过在剧烈超声处理和苛刻化学条件下测试F-PVA纳米纤维膜，证实了ENMs对MD的强大超疏水性。此外，真空膜蒸馏实验表明，F-PVA膜呈现出25.2 kg/m² h的高且稳定的渗透通量，比商业PTFE膜高70%，在16小时的连续测试（以3.5 wt% NaCl为进料溶液，进料温度和渗透压力分别设定为333 K和9 kPa）期间，渗透液电导率令人满意（<5 μm/cm），表明它们在诸如高盐度水脱盐和挥发性有机化合物去除等众多MD过程中具有巨大潜力。
