| Project/Area Number |
23K19184
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| Research Category |
Grant-in-Aid for Research Activity Start-up
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| Allocation Type | Multi-year Fund |
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| Review Section |
0401:Materials engineering, chemical engineering, and related fields
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| Research Institution | Kobe University |
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Principal Investigator |
ZHANG PENGFEI 神戸大学, 先端膜工学研究センター, 特命助教 (00979156)
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| Project Period (FY) |
2023-08-31 – 2025-03-31
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| Project Status |
Granted (Fiscal Year 2023)
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| Budget Amount *help |
¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2024: ¥520,000 (Direct Cost: ¥400,000、Indirect Cost: ¥120,000)
Fiscal Year 2023: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
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| Keywords | Membrane distillation / Hollow fiber membranes / Fluoroalkylsilane / Omniphobic / Anti-wetting |
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| Outline of Research at the Start |
This proposal plans to utilize the co-extrusion technique to prepare PVDF membrane with a hierarchical structure and entraped nanoparticles on surface. And Subsequent simple fluorination process will endow surface with omniphobic property achieving anti-wetting/scaling performance for MD process.
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| Outline of Annual Research Achievements |
For this project, it would like to address the challenge of wetting and scaling in membrane distillation (MD) by developing a robust superhydrophobic poly(vinylidene fluoride) (PVDF) hollow fiber membrane. To achieve this, a hierarchical outer surface of PVDF membrane was built by extruding SiO2 suspension at the outermost layer of a triple-orifice spinneret, then 1H,1H,2H,2H-perfluorooctyltrichlorosilane (FAS) was employed to further lower membrane surface energy. The surface roughening and superhydrophobicity are achieved through chemical bonding for enhancement of anti-wetting and anti-scaling properties of PVDF hollow fiber membrane. This straightforward and scalable approach may be applicable for various polymers to produce robust superhydrophobic membranes for MD applications.
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| Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
Until now, it was found that the fabricated membrane displayed a high contact angle of 153°, 147° and 141° for water, SDS solution (0.4 mM) and saline SDS solution (0.4 Mm SDS and 35wt% NaCl), respectively, showing higher liquid entry pressure. Direct contact membrane distillation (DCMD) experiments demonstrated that PVDF/FAS membrane illustrated excellent wetting resistance to seawater (3.5 wt% of NaCl) containing SDS of a progressively increased concentration. Furthermore, it also retarded the CaSO4 scaling through reducing not only heterogeneous nucleation but also the tendency of bulk crystal deposition on membrane outer surface. Finally, DCMD process using a hypersaline solution with NaCl concentration of 23.1 wt% was conducted using PVDF/FAS membrane for nearly 30 hours. It could be found that the hypersaline solution didn’t affect the anti-wetting properties of PVDF/FAS membrane, maintaining a stable MD flux around and salt rejection above 99.2%.
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| Strategy for Future Research Activity |
The hierarchical surface structure constructed by SiO2 and the presence of low-surface-energy FAS on the membrane's outer surface exhibited an improved anti-scaling property for the PVDF/FAS membrane. This indicates that the combination of co-extrusion technology and fluorination treatment provides a simple and feasible route for manufacturing high-performance MD membranes with nanostructured surface characteristics using different membrane materials. But current superhydrophobic membrane needs two steps during membrane preparation. At the same time, we found that only extruding different solvents on the membrane surface is the superhydrophobic PVDF membrane. Therefore, we will next focus on the preparation of superhydrophobic PVDF membrane directly from the three-well filament head and investigate its anti-scaling and anti-wetting properties in the membrane distillation process by optimizing the type of the outermost layer solvent and preparation conditions.
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