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Effect of hydrophilic silica and dual coagulation bath on structural and mechanical properties of PVDF membrane for membrane distillation
Journal of Environmental Health Science and Engineering ( IF 3.0 ) Pub Date : 2020-09-06 , DOI: 10.1007/s40201-020-00477-w
Mohammad Hossein Emamirad 1 , Sirus Javadpour 1
Affiliation  

The water scarcity threatens environmental health and human development. Membrane distillation (MD) is one of the most applicable processes for purifying water using a hydrophobic membrane. In this study, the synergetic effect of SiO2 nanoparticles as well as employing the dual coagulation bath on physical and mechanical properties of Polyvinylidene Fluoride (PVDF) flat-sheet membranes produced by dry-wet phase inversion (DIPS) technique has been investigated. The results of microstructural analysis using Scanning Electron Microscope (SEM) demonstrated that by adding nanoparticles while the pore size decreased noticeably, the percentage of porosity significantly increased. Also, it has been revealed that by utilizing isopropanol as the first coagulation bath the finger-like macro-voids became smaller in size, and the share of sponge-like structures rose remarkably. The membrane performance was tested by Vacuum Membrane Distillation (VMD) for measuring the flux and Liquid Entry Pressure (LEPw) laboratory setup. It can be seen that by increasing the content of SiO2 nanoparticles to 6 wt.% while the LEPw approximately halved, the flux soared to about 10000 g/m2h. Moreover, mechanical testing showed that although the tensile strength of nanocomposite samples fabricated in isopropanol dual coagulation bath was improved by up to 66%, their ductility slightly declined. Furthermore, the hydrophobicity of each membrane was examined via contact angle measurements. Finally, it was found that all membranes completely rejected the NaCl in rejection test.



中文翻译:

亲水性二氧化硅和双凝固浴对膜蒸馏PVDF膜结构和力学性能的影响

水资源短缺威胁着环境健康和人类发展。膜蒸馏 (MD) 是使用疏水膜净化水的最适用工艺之一。在本研究中,SiO 2的协同作用纳米粒子以及采用双凝固浴对通过干湿相转化 (DIPS) 技术生产的聚偏二氟乙烯 (PVDF) 平板膜的物理和机械性能进行了研究。使用扫描电子显微镜 (SEM) 进行的微观结构分析结果表明,通过添加纳米颗粒,在孔径显着减小的情况下,孔隙率显着增加。此外,已经表明,通过使用异丙醇作为第一凝固浴,指状大空隙的尺寸变小,海绵状结构的份额显着增加。膜性能通过真空膜蒸馏 (VMD) 测试,用于测量通量和液体进入压力 (LEP w) 实验室设置。可以看出,通过将 SiO 2纳米颗粒的含量增加到 6 wt.% 而 LEP w大约减半,通量飙升至约 10000 g/m 2 h。此外,力学测试表明,虽然在异丙醇双凝固浴中制备的纳米复合材料样品的拉伸强度提高了 66%,但其延展性略有下降。此外,通过接触角测量检查每个膜的疏水性。最后,发现所有膜在排斥试验中完全排斥NaCl。

更新日期:2020-09-07
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