To fine-tune pore size and hydrophobicity of self-sustained PVDF membranes: A study on non-solvent reuse and air exposure time

Articles in Press

Document Type : Research Paper

Authors

1 NPRL, Tehran, Iran

2 Amirkabir University of Technology, Tehran, Iran

3 Membrane Processes Research Laboratory (MPRL), Department of Chemical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran

4 University Complutense of Madrid, Spain

Abstract

Polyvinylidene fluoride (PVDF) membranes were fabricated to engineer superhydrophobic/highly hydrophobic membranes with tunable pore size deploying non-solvent reuse, air exposure time, and low strength non-solvents. Non-solvent was reused several times to reach a point where a textured surface was formed. Air exposure time was investigated to tune pore size and hydrophobicity. Membrane shrinkage was minimized by drying membranes on glass plates and removing them with the help of distilled water/isopropyl alcohol (IPA) spraying. Water contact angles (WCA) as high as ~155° were achieved for the PVDF membranes formed with non-solvent reuse and low-strength non-solvents regardless of the applied non-solvents or solvents. It is also observed that polymer dissolution temperature had no effect on final membrane characteristics. However, by increasing the air exposure time, the surface hydrophobicity was reduced. Long-term direct contact membrane distillation (DCMD) tests were conducted observing robust desalination performance with stable DCMD flux and salt rejection considering a transmembrane temperature difference of 40 ℃. To the best of authors’ knowledge, this is the first report focusing on the non-solvent reuse and air exposure time effect using low-strength non-solvents to tune hydrophobicity and pore size to pave the way to fabricate membrane with reduced environmental impact and improved physical characteristics.

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Main Subjects

Journal of Membrane Science and Research

Articles in Press, Accepted Manuscript
Available Online from 23 March 2024

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History

  • Receive Date: 03 January 2024
  • Revise Date: 23 March 2024
  • Accept Date: 23 March 2024

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