Jiao, Shichao
(2023)
Particle-Based Porous Material Development for Capillary Condensation Applications.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
The 21st-century challenge of securing an abundant fresh water supply has led to a growing trend of harnessing atmospheric water. Water scavenging approaches have primarily leveraged daily heating/cooling cycles, using techniques such as mimicking desert beetles to capture early-morning fog using synthetic netting or biomimetic materials, and exploiting solar energy more to enhance water release from metal-organic framework (MOF) based sorbent materials. We describe a facile way to control capillary condensation via confined geometric structures, using this behavior to create novel composite materials for water scavenging. By employing a particle self-assembly technique, we fabricate porous materials with well-defined, controllable pore sizes. Controlling the scale and number of confined spaces allows direct control of capillary condensation behavior. We predict capillary condensation induced by exposing these materials to a humid environment, with water uptake isotherms qualitatively agreeing with predictions across all samples.
Our novel water-scavenging composite is created by forming a hierarchically ordered porous material from a suitable hydrogel and embedding closely packed particles within its surfaces. This configuration amplifies native material performance and realizes synergy between the capture and storage of scavenged water. The composite can capture moisture at a significantly lower relative humidity than native materials alone. Although challenges like insufficient mechanical strength and the need for scalable methods remain, our composite demonstrates superior efficiency under ideal conditions compared to state-of-the-art materials. This approach has potential for a cheap, low-energy clean water source and could be adapted for various condensible vapor reclamation applications.
Finally, we computationally examine the phenomenon of "lubrication collapse" that underpins the particle self-assembly approach. By studying a range of forcing patterns and strengths for confined particle-laden flows, we identify cases where the one-particle Stokes number allows particles to cross fluid streamlines and collide, while the two-particle Stokes number ensures viscous interactions significantly reduce relative particle velocities. Manipulating flow parameters in this manner helps devise criteria for generating flows that lead to local enrichment or complete dispersion of included particles.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
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| ETD Committee: |
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| Date: |
13 June 2023 |
| Date Type: |
Publication |
| Defense Date: |
19 January 2023 |
| Approval Date: |
13 June 2023 |
| Submission Date: |
28 March 2023 |
| Access Restriction: |
1 year -- Restrict access to University of Pittsburgh for a period of 1 year. |
| Number of Pages: |
106 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Swanson School of Engineering > Chemical and Petroleum Engineering |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
Water, Absorption, Composites, Humidity, Hydrogels, Porous Materials, CFD, Simulation |
| Date Deposited: |
13 Jun 2024 05:00 |
| Last Modified: |
13 Jun 2024 05:15 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/44367 |
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