Anisotropic performance of a superhydrophobic polyvinyl difluoride membrane with corrugated pattern in direct contact membrane distillation
Anisotropic performance of a superhydrophobic polyvinyl difluoride membrane with corrugated pattern in direct contact membrane distillation
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DOI：
10.1016/j.desal.2020.114363
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发表时间：
2020-05
期刊：
影响因子：
9.9
通讯作者：
Yongjie Liu;Jin Wang;Zechun Xiao;Li Liu;Dongdong Li;Xuemei Li;Huabing Yin;T. He
中科院分区：
文献类型：
--
作者：
Yongjie Liu;Jin Wang;Zechun Xiao;Li Liu;Dongdong Li;Xuemei Li;Huabing Yin;T. He
采用微模塑相分离技术制备了一种新型的表面波纹状超疏水聚偏氟乙烯（PVDF）膜（C-PVDF），用于直接接触膜蒸馏（DCMD）。膜显示出159.0 ± 4.0°的静态接触角。然而，滑动角的动态测量显示，当水滴平行于脊滑动时，滑动角的值较低，为9.1 ± 0.8°，而垂直于脊滑动时，滑动角的值较高，为14.6 ± 1.6°。这种各向异性的性质也反映在DCMD通量的进料的去离子水和4.0重量%的NaCl溶液：在进料平行于脊流动的情况下，导致更高的通量比它垂直于脊流动。各向异性MD性能不能用含尘气体模型来解释，因为模型中膜的平均特性对于两种流动模式本质上是相同的。相反，在平行和垂直方向上的各向异性润湿和滑动揭示了MD性能具有热力学和流体动力学起源。
A novel surface-corrugated superhydrophobic polyvinylidene fluoride (PVDF) membrane (C-PVDF) was prepared for direct contact membrane distillation (DCMD) using a micromolding phase separation (μPS) method. The membrane showed a static contact angle of 159.0 ± 4.0°. However, dynamic measurements of the sliding angles revealed a lower value of 9.1 ± 0.8° when a water droplet slides in parallel to the ridge, and a higher value of 14.6 ± 1.6° if perpendicular to the ridge. This anisotropic property was also reflected in the DCMD fluxes for both feed of deionized water and 4.0 wt% NaCl solution: in case the feed flows in parallel to the ridge, a higher flux is resulted than it flows perpendicular to the ridge. Anisotropic MD performance cannot be explained by the Dusty-Gas model because the average characteristics of the membrane in the model are intrinsically the same for both flow modes. Instead, anisotropic wetting and sliding in the parallel and perpendicular orientation revealed that the MD performance has both thermodynamic and hydrodynamic origins.