Fabrication and surface characterization of lignin-polyamide thin film composite membrane for reverse osmosis desalination

Document Type : Research Paper

Authors

1 1. Industrial Technology Development Institute, DOST Compound, Gen. Santos Ave., Bicutan, Taguig City, Metro Manila, Philippines 2. School of Chemical, Biological, and Materials Engineering and Sciences, Mapua University, Intramuros,

2 Industrial Technology Development Institute, DOST Compound, Gen. Santos Ave., Bicutan, Taguig City, Metro Manila, Philippines

3 School of Chemical, Biological, and Materials Engineering and Sciences, Mapua University, Intramuros, Manila, Philippines

Abstract

Altering the intrinsic properties of thin film composites by integrating different nanoparticles has been widely explored in recent years. Sodium lignosulfonate (NaLS), lignin extracted by the sulfite process, as selected in this study because of its complex structure which contains both hydrophobic and hydrophilic moieties.



NaLS was subjected to wet milling with n-hexane for 3 hours and 5 hours to reduce particle dimension to sub-micron size. The mechanical treatment has produced a mixture of spherical and angular/elongated particles with average size distributions of 408 nm for 3 hours of milling and 234 nm for 5 hours of milling. The polyamide selective layers with different concentrations of NaLS incorporated into the organic phase or aqueous phase, were impregnated to the polysulfone support through conventional and spray-assisted interfacial polymerization22 (IP), respectively. The resulting composites fabricated through spray-based IP were observed to have rougher surfaces, Ra = 165 nm – 701 nm. Increased concentration of NaLS produced lower contact angles of 75.38° to 87.82° while the controls exhibited the highest readings ranging from 92.38° to 110.42°. Increased water flux and salt rejection were also observed for the modified PA-lignin TFC due to the enhanced hydrophilicity and a more negative surface charge.

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Articles in Press, Accepted Manuscript
Available Online from 24 April 2023
  • Receive Date: 21 March 2023
  • Revise Date: 14 April 2023
  • Accept Date: 24 April 2023
  • First Publish Date: 24 April 2023