| NSF Org: |
CBET Division of Chemical, Bioengineering, Environmental, and Transport Systems |
| Recipient: |
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| Initial Amendment Date: | June 6, 2014 |
| Latest Amendment Date: | June 6, 2014 |
| Award Number: | 1402772 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Christina Payne
cpayne@nsf.gov (703)292-2895 CBET Division of Chemical, Bioengineering, Environmental, and Transport Systems ENG Directorate for Engineering |
| Start Date: | July 1, 2014 |
| End Date: | June 30, 2018 (Estimated) |
| Total Intended Award Amount: | $227,788.00 |
| Total Awarded Amount to Date: | $227,788.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
1600 HAMPTON ST COLUMBIA SC US 29208-3403 (803)777-7093 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
SC US 29208-0001 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | Interfacial Engineering Progra |
| Primary Program Source: |
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| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.041 |
ABSTRACT
PI: Yu, Miao / Liang, Xinhua
Proposal Number: 1402772 / 1402122
Title: Collaborative Research: Advanced Zeolite-Composite Adsorbents with Fine-Tuned Pore Sizes for Molecular Sieving Separations
Mixture separation constitutes a large and costly component of industrial processes. Various separation technologies, such as distillation, extraction, adsorption, and membrane separation, have been developed to separate mixtures utilizing different properties of components in the mixture. Among these technologies, separation processes based on adsorption, such as pressure swing adsorption (PSA) and temperature swing adsorption (TSA), have been widely used in industry. Development of more energy-efficient adsorptive gas separation processes strongly depends on the development of improved porous adsorbents, and porous adsorbents with favorable adsorption isotherms and selectivity for the separation of interest are always the focus of adsorption-based separation processes. Zeolites are one of the most promising adsorbents that may realize true molecular-sieving separation under harsh separation conditions, attributing to their uniform, molecular-sized pores and high chemical, thermal and mechanical stabilities. Despite of a large selection pool of zeolites/molecular sieves and available techniques to adjust their pore sizes, not all desired pore sizes can be obtained for target separations, especially for separation of molecules with very close sizes, such as N2 (kinetic diameter: 0.364 nm)/CH4 (0.38 nm), O2 (0.346 nm)/N2, and paraffin/olefin. Therefore, it is highly desirable to develop new strategies to further fine-tune the pore sizes of zeolite-based materials and fill the pore size gaps between different zeolites. The goal of this proposed research is to fine-tune the pore entrance of zeolites by depositing ultrathin microporous coatings to achieve effective separation for industrially important mixtures that traditional zeolites have difficulty to separate.
Ultrathin microporous coatings will be deposited using molecular layer deposition (MLD) on the zeolites to fill the pore-size gaps between different zeolites an obtain enhanced fundamental understanding of deposition mechanisms and coating interactions with zeolite substrates. Specifically, the objectives of the proposed research are: (1) To develop a reliable and reproducible MLD process to deposit ultrathin organic/inorganic hybrid films (with precisely controlled properties) on zeolite substrates and obtain a fundamental understanding on the factors that affect the quality of MLD coatings; (2) To elucidate and understand the decomposition of hybrid MLD coating and pore-generation mechanisms under different conditions; (3) To characterize effective pore sizes of zeolite-composite adsorbents and establish the fundamental coating property-pore entrance size relationship; and (4) To rationally design zeolite composite adsorbents with desired pore sizes and investigate separation performance for target mixtures. This completely new concept may lead to effective adsorptive separation of difficult-to-separate mixtures.
This proposed research is expected to have great scientific as well as technological impact on the synthesis of nanostructured zeolite-composite adsorbents with fine-tuned pore sizes for mixture separations and potentially for selective catalysis. If successful, the project will greatly benefit adsorption-based separation processes. It will represent a significant advance in the rational design of zeolite-based adsorbents. The proposed research has significant practical implications on industrially important gas mixture separations. It is anticipated that this study could serve as a model for the rational design of advanced sorbents for adsorption-based separation processes.
The PIs have specific defined plans to engage a broad range of students in learning about nanomaterials and molecular sieves. Specific opportunities for minorities will be funded through targeted scholarships and projects during the summer. Both PIs are active in outreach programs for K-12 students in mainly underrepresented populations in the areas of both universities.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
Mixture separation constitutes a large and costly component of industrial processes. This proposed research is expected to have great scientific as well as technological impact on the synthesis of nanostructured zeolite-composite adsorbents with fine-tuned pore sizes for mixture separations, and may greatly benefit the chemical engineering industry, especially the adsorption-based separation processes.
The goal of this proposed research is to fine-tune the pore entrance sizes of zeolites by depositing ultrathin microporous coatings by molecular layer deposition (MLD), as shown schematically in Figure 1, to achieve effective separation of industrially important mixtures that traditional zeolites have difficulty to separate, via enhanced understanding on mechanisms of porous coating deposition and interactions between microporous coatings and zeolite substrates. Misalignment of the micropores of the coatings with zeolite crystal pores is expected to slightly reduce zeolite substrate pores, and the degree of misalignment might be fine-tuned by adjusting coating properties (thickness, composition, and pore size). This novel strategy for fine-tuning zeolite pore entrance sizes has considerable potential for filling the pore size gaps between different zeolites and, thus, may have great impact on separating difficult-to-separate mixtures, such as N2/CH4, O2/N2, paraffin/olefin (propane/propylene, ethane/ethylene, etc.).
In this project, We have deposited MLD coatings on 5A and 13X zeolites. By adjusting alumina MLD coating thickness, we have shown that 5A zeolite pore mouth can be continuously adjusted to distinguish molecules with size difference as small as 0.01 nm. By depositing a thin Titania MLD coating, we have shown propane/propylene adsorptive selectivity can by significantly increased. By varying calcination temperature for Titania MLD coatings, we have shown significantly improved CO2/N2 adsorptive separation performance. We also showed MLD can be combined with atomic layer deposition (ALD) to further fine tune the MLD modified zeolite pore size; significantly improved propylene/propane separation was demonstrated, with adsorption selectivity as high as 30, in contrast with ~1 for 5A and ~6 for MLD modified 5A. In addition, we demonstrated microporous Titania MLD coating can be used a continuous membrane for removing small organic contaminant in water. Four papers have been published, one patent has been issued, and one manuscript is under preparation for submission. Under the support of this NSF funding, two graduate students have participated in the project, and one has graduated with a Ph.D. degree.
Last Modified: 09/23/2018
Modified by: Miao Yu
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