Open AccessEffect of hydrophilic silica and dual coagulation bath on structural and mechanical properties of PVDF membrane for membrane distillation
Author(s) -
Mohammad Hossein Emamirad,
Sirus Javadpour
Publication year - 2020
Publication title -
journal of environmental health science and engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.447
H-Index - 45
ISSN - 2052-336X
DOI - 10.1007/s40201-020-00477-w
Subject(s) - membrane , membrane distillation , polyvinylidene fluoride , phase inversion , materials science , scanning electron microscope , coagulation , chemical engineering , ultimate tensile strength , nanoparticle , composite material , porosity , nanocomposite , chromatography , chemistry , nanotechnology , desalination , polymer , psychology , biochemistry , psychiatry , engineering
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 SiO 2 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 (LEP w ) laboratory setup. It can be seen that by increasing the content of SiO 2 nanoparticles to 6 wt.% while the LEP w approximately halved, the flux soared to about 10000 g/m 2 h. 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. Graphical abstract.