Template-Free Synthesis of Oriented Zeolite Membranes with Improved High-Activity Molecular Separation Characteristics

无模板合成具有改进的高活性分子分离特性的定向沸石膜

• 批准号: 2031087
• 负责人: Jerry Lin
• 金额: $ 34.11万
• 依托单位: Arizona State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-05-15 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2031087&HistoricalAwards=false
• 关键词: Template; Free; Synthesis; Oriented; Zeolite

MFI-type zeolite membranes are among the most stable microporous materials with molecular sieving capabilities. High-performing MFI zeolite membranes on hollow fiber supports will enable development of new and more efficient separation technologies for the chemical and petroleum industries by significantly improving purity, heightening flux, and minimizing capital and operating costs. Due to the unique pore structure of MFI zeolite crystals, b-oriented MFI zeolite membranes offer better molecular sieving separation characteristics than randomly oriented polycrystalline MFI zeolite membranes. These properties make b-oriented MFI zeolite membranes highly attractive for industrial applications including separation of xylene isomers. However, high quality b-oriented MFI zeolite membranes have been fabricated only on disk supports by complex synthesis methods that include the use of costly organic-templates. Such templated MFI zeolite membranes also exhibit unfavorable pressure dependence of separation properties, characterized by a decrease of permeability and selectivity with increasing feed xylene vapor pressure. Several challenges must be addressed to further advance the synthesis of b-oriented MFI zeolite membranes beyond the laboratory scale. These challenges include synthesis of high-quality b-oriented MFI zeolite membrane on supports that can be arranged into modules with high packing density by cost-effective and scalable methods and understanding the separation characteristics of b-oriented MFI zeolite membranes in contact with feed mixtures at high vapor pressures. This project will therefore develop methods for facile syntheses of high-quality b-oriented MFI zeolite membranes on hollow fiber supports and study the synthesis-structure-separation property relationship of such grown b-oriented MFI zeolite membranes for use in the separation of xylene isomers at high vapor pressures. The knowledge developed through this project will be translatable to other-oriented crystalline microporous membranes for other separation processes. In addition to graduate student training opportunities, the broader impacts of the project include a public outreach activity aimed at demonstrating how inorganic membranes work.This project will focus on the synthesis of b-oriented MFI zeolite membranes on alumina hollow fiber supports by a scalable, template-free synthesis method. The method will consist of filtration “seeding” using 2-dimensional MFI zeolite nanosheets, followed by template-free secondary growth. Preparation of a zeolite layer using 2-dimensional MFI zeolite nanosheets by filtration offers a versatile and scalable method of fabrication leading to a high-quality b-oriented MFI zeolite seed layer for secondary growth. The MFI zeolite seed layer will be preferentially grown into a b-oriented MFI zeolite membrane with a template-free synthesis solution of optimized composition. The use of a template-free solution produces zeolite membranes of higher quality by minimizing or eliminating intercrystalline gaps that permit non-selective diffusion of gas or liquid mixtures. It also reduces the number of synthesis steps and eliminates the use of costly organic templates. Synthesis of templated and template-free, randomly and b-oriented MFI zeolite membranes enables a systematic study of the synthesis-structure-separation property relationship of the MFI zeolite membranes. In particular, the study will be focused on understanding the effects crystal shape/orientation, intercrystalline microstructure, and zeolite framework composition on the feed pressure dependence of xylene permeability and selectivity of MFI zeolite membranes. This work will also identify conditions for the synthesis of high-performance b-oriented MFI zeolite membranes for effective separation of xylene mixture under industrially relevant conditions.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

MFI型沸石机制是具有分子筛分能力的最稳定的微孔材料之一。空心纤维载体上的高效MFI沸石机制将通过显着提高纯度，提高通量以及最小化资本和运营成本来开发新的，更有效的分离技术，从而为化学和石油行业提供更高的分离技术。由于MFI沸石晶体的独特孔结构，与随机定向的多晶MFI沸石机制相比，面向B的MFI沸石机制可提供更好的分子筛分分离特性。这些特性使面向B的MFI沸石机制在工业应用中具有极具吸引力，包括分离二甲苯异构体。但是，仅通过复杂的合成方法在磁盘支持上制造了高质量的B面向MFI沸石机制，其中包括使用昂贵的有机 - 振荡。这种模板的MFI沸石膜也表现出分离特性的不利压力依赖性，其特征是随着饲料二甲苯蒸气压的增加，渗透性和选择性的降低。必须提出一些挑战，以进一步推进将B-面向B的MFI沸石膜的合成以外的实验室规模。这些挑战包括合成高质量的B-面向B型MFI沸石膜上的支撑物，可以通过具有成本效益和可扩展的方法排列到具有高包装密度的模块中，并了解与B-型MFI Zeolite机械机制的分离特性，并与高蒸发混合物接触到高蒸发混合物。因此，该项目将开发用于空心纤维支持的高质量B型MFI沸石机制的可容纳合成的方法，并研究这种成长的B型B-opentiendiendiendiended B-Tienged MFI Zeolite机制的合成结构分离性质关系，用于在高伏型Isomers分离高蒸气的二甲苯酶分离中。通过该项目发展的知识将可以转换为其他面向其他分离过程的晶体微孔膜。除了研究生培训机会外，该项目的更广泛影响包括旨在证明无机膜如何起作用的公共外展活动。该项目将重点介绍通过可扩展的，模板的无空合合成方法对氧化铝空心纤维的合成对氧化铝的空心纤维的合成。该方法将包括使用二维MFI沸石纳米片的过滤“播种”，然后使用无模板的二级生长。通过过滤使用二维MFI沸石纳米片制备沸石层，提供了一种多功能且可扩展的制造方法，导致高质量的B型MFI沸石种子层以用于二级生长。 MFI沸石种子层将优先生长到具有优化组合物的无模板合成溶液中，将其生长到面向B的MFI沸石膜中。使用无模板溶液的使用可通过最大程度地减少或消除允许无气体或液体混合物的非选择性扩散的晶体间间隙来产生更高质量的沸石膜。它还减少了合成步骤的数量并消除了昂贵的有机模板的使用。无模板和模板无模板，随机和面向B的MFI沸石机制的合成能够对MFI沸石机制的合成结构分离性质关系进行系统研究。特别是，该研究将集中在理解晶体形状/方向，晶间微观结构以及沸石框架组成上对二甲苯渗透性和MFI沸石机制的选择性的依赖性的效果。这项工作还将确定综合高性能B-面向B-面向MFI沸石膜，以有效地分离在工业相关条件下的二甲苯混合物。该奖项反映了NSF的法定任务，并已通过评估基金会的知识和更广泛的影响来诚实地认为，通过评估来诚实地支持了审查审查的审查。

项目成果

B-oriented MFI zeolite membranes for xylene isomer separation - Effect of xylene activity on separation performance

用于二甲苯异构体分离的 B 取向 MFI 沸石膜 - 二甲苯活性对分离性能的影响

• DOI: 10.1016/j.memsci.2022.120492
• 发表时间: 2022
• 期刊: Journal of membrane science
• 影响因子: 9.5
• 作者: Fateme Banihashemi;Jerry Y.S. Lin
• 通讯作者: Jerry Y.S. Lin