Water as the Pore Former in the Synthesis of Hydrophobic PVDF Flat Sheet Membranes for Use in Membrane Distillation


  • Lebea Nathnael Nthunya Department of Chemical, Metallurgical and Material Engineering, Tshwane University of Technology, Private Bag x680, Pretoria, 0001, South Africa
  • Leonardo Gutierrez Particle and Interfacial Technology Group, Department of Applied Analytical and Physical Chemistry, Ghent University, Coupure Links 653, 9000 Ghent, Belgium;Facultad del Mar y Medio Ambiente, Universidad del Pacifico, Guayaquil, Ecuador
  • Edward N. Nxumalo Nanotechnology and Water Sustainability Research Unit, College of Science, Engineering and Technology, University of South Africa, Florida, 1709, Johannesburg, South Africa
  • Sabelo D. Mhlanga DST/MINTEK Nanotechnology Innovation Centre, Strijdom Park, Randburg, 2125, Johannesburg, South Africa




Although PVDF flat sheet membranes have been widely tested in MD, their synthesis and modifications currently require increased use of green and inexpensive materials. In this study, flat sheet PVDF membranes were synthesized using phase inversion and water as the pore former. Remarkably, the water added in the casting solution improved the membrane pore sizes; where the maximum pore size was 0.58 µm. Also, the incorporation of f-SiO2NPs in the membrane matrix considerably enhanced the membrane hydrophobicity. Specifically, the membrane contact angles increased from 96° to 153°. Additionally, other parameters investigated were mechanical strength and liquid entry pressure (LEP). The maximum recorded values were 2.26 MPa and 239 kPa, respectively. The modified membranes (i.e., using water as the pore former and f-SiO2NPs) were the most efficient, showing maximum salt rejection of 99.9% and water flux of 11.6 LMH; thus, indicating their capability to be used as efficient materials for the recovery of high purity water in MD.


Direct contact membrane distillation, PVDF flat sheet membranes, superhydrophobic silica nanoparticles, water as the pore former


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