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4. Efficacy of Electrically-Polarized 3D Printed Graphene-blended Spacers on the Flux Enhancement and Scaling Resistance of Water Filtration Membranes

Author

Yanar, Numan, Park, Hosik, Son, Moon, and Choi, Heechul

Subjects
Condensed Matter - Soft Condensed Matter
Abstract

In this research, an electrically-polarized graphene-polylactic acid (E-GRP) spacer is introduced for the first time by a novel fabrication method, which consists of 3D printing followed by electrical polarization under a high voltage electric field (1.5 kV/cm). The fabricated E-GRP was tested in an osmotic-driven process (forward osmosis system) to evaluate its performance in terms of water flux, reverse solute flux, and ion attraction compared to a 3D printed non-polarized graphene-polylactic acid (GRP) spacer and a polylactic acid (PLA) spacer. The use of the developed E-GRP spacer showed > 50% water flux enhancement (32.4 +- 2 LMH) compared to the system employing the GRP (20.5 +- 2.3 LMH) or PLA (20.8 +- 2.1 LMH) spacer. This increased water flux was attributed to the increased osmotic pressure across the membrane due to the ions adsorbed on the polarized (E-GRP) spacer. The E-GRP spacer also retarded the gypsum scaling on the membrane compared to the GRP spacer due to the dispersion effect of electrostatic forces between the gypsum aggregation and negatively charged surfaces. The electric polarization of the E-GRP spacer was shown to be maintained for > 100 h by observing its salt adsorption properties (in a 3 M NaCl solution)., Comment: Supplementary figures are given at the end

Published
2020

36. Autonomous Interfacial Assembly of Polymer Nanofilms via Surfactant-Regulated Marangoni Instability

Author

Park, Sung-Joon, Lee, Myung-Seok, Kilic, Mehmet Emin, Ryu, Junil, Park, Hosik, Park, You In, Kim, Hyoungsoo, Lee, Kwang-Ryeol, Lee, Jung-Hyun, Park, Sung-Joon, Lee, Myung-Seok, Kilic, Mehmet Emin, Ryu, Junil, Park, Hosik, Park, You In, Kim, Hyoungsoo, Lee, Kwang-Ryeol, and Lee, Jung-Hyun

Abstract

Interfacialpolymerization (IP) provides a versatile platform forfabricating defect-free functional nanofilms for various applications,including molecular separation, energy, electronics, and biomedicalmaterials. Unfortunately, coupled with complex natural instabilityphenomena, the IP mechanism and key parameters underlying the structuralevolution of nanofilms, especially in the presence of surfactantsas an interface regulator, remain puzzling. Here, we interfaciallyassembled polymer nanofilm membranes at the free water-oilinterface in the presence of differently charged surfactants and comprehensivelycharacterized their structure and properties. Combined with computationalsimulations, an in situ visualization of interfacial film formationdiscovered the critical role of Marangoni instability induced by thesurfactants via various mechanisms in structurally regulating thenanofilms. Despite their different instability-triggering mechanisms,the delicate control of the surfactants enabled the fabrication ofdefect-free, ultra-permselective nanofilm membranes. Our study identifiescritical IP parameters that allow us to rationally design nanofilms,coatings, and membranes for target applications.

Published
2023
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