Adsorbed-Induced Changes in Zeolite Membrane Structures

吸附引起的沸石膜结构变化

• 批准号: 0730047
• 负责人: John Falconer
• 金额: --
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-10-01 至 2010-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0730047&HistoricalAwards=false
• 关键词: Adsorbed; Induced; Changes; Zeolite; Membrane

PROPOSAL NUMBER: 0730047PRINCIPAL INVESTIGATOR: John FalconerINSTITUTION: University of ColoradoPROPOSAL TITLE: Adsorbed-Induced Changes in Zeolite Membrane Structures The main goals of this project are: (1) to better understand how zeolite membranes work and how non-zeolitic pores affect separations, (2) to understand how adsorbed-induced crystal expansion and shrinkage of non-zeolitic pores change separation selectivities, (3) improve separation selectivities by adding a third component to a binary (or multi-component) mixture to take advantage of these adsorbed-induced changes, and (4) to develop better characterization methods for zeolite membranes. The project will build on the recent discovery that adsorption of certain molecules (e.g., n-hexane, n-octane) in MFI zeolite membranes swells the MFI crystals slightly (~1% linear expansion), and this expansion shrinks the size of the non-zeolitic pores (defects) sufficiently to dramatically decrease permeation through non-zeolitic pores. The successful completion of this research will result in new understanding of the micro-structure of zeolite membranes, will indicate directions for improved zeolite membrane preparation, and will potentially result in new methods of zeolite membrane separations by addition of certain molecules to mixtures. It will identify molecules that can cause improved selectivity by shrinking the size of non-zeolitic pores. Comparing membranes prepared in different laboratories is difficult, and characterization methods that measure flux through non-zeolitic pores and measure their pore sizes will be developed. MFI membranes with different fractions of their flow through non-zeolitic pores will be used. Methods to measure changes due to adsorption, for crystals or membranes, include XRD, TPD, and confocal microscopy. Permeation methods include pervaporation to obtain high adsorbed loadings, which are more representative of industrial applications, vapor permeation as a function of pressure (and capillary condensation in non-zeolitic pores), permporosimetry, and transient permeation of mixtures with mass spectrometer detection. Separations will be carried out by pervaporation for binary and ternary mixtures. Separations use a significant fraction of the energy in the US, and membrane separations have the potential to significantly reduce that usage. Understanding adsorbed-induced microstructural changes in zeolite membranes will impact how zeolite membranes are prepared and utilized. Zeolite membranes have the potential to separate organic isomers (structural and stereo isomers), and azeotropes, and these abilities combined with their high temperature stability give them significant advantages over polymer membranes. Zeolite layers have potential applications for hydrogen storage and in micro devices. Continuation of membrane technology patents having the potential to rapidly and directly benefiting society through commercialization is anticipated. It is anticipated that at least one student will be supported by a GAANN fellowship, which has K-12 and community outreach as one of the required aspects. Undergraduate students will be supported, and one high school student will be involved in this research each summer.

提案编号：0730047主要研究者：John Falconer研究机构：科罗拉多大学提案标题：沸石膜结构的吸附诱导变化本项目的主要目标是：（1）为了更好地理解沸石膜如何工作以及非沸石孔如何影响分离，（2）为了理解非沸石孔的吸附诱导的晶体膨胀和收缩如何改变分离选择性，（3）通过向二元（或多组分）混合物中加入第三组分以利用这些吸附诱导的变化来提高分离选择性，以及（4）开发用于沸石膜的更好的表征方法。该项目将建立在最近的发现，吸附某些分子（例如，正己烷、正辛烷）使MFI晶体轻微溶胀（~1%线性膨胀），并且这种膨胀使非沸石孔（缺陷）的尺寸充分收缩，从而显著降低通过非沸石孔的渗透。本研究的成功完成将导致对沸石膜的微观结构的新的理解，将指示改进沸石膜制备的方向，并且将潜在地导致通过向混合物中添加某些分子来进行沸石膜分离的新方法。它将确定可以通过缩小非沸石孔的尺寸来提高选择性的分子。比较不同实验室制备的膜是困难的，将开发测量通过非沸石孔的通量和测量其孔径的表征方法。 将使用具有通过非沸石孔的不同流量分数的MFI膜。测量由于晶体或膜的吸附而引起的变化的方法包括XRD、TPD和共聚焦显微镜。渗透方法包括渗透蒸发以获得高吸附负载，其更代表工业应用，作为压力的函数的蒸气渗透（和非沸石孔中的毛细管冷凝），渗透率测定法，和用质谱仪检测的混合物的瞬时渗透。二元和三元混合物的分离将通过渗透蒸发进行。在美国，分离使用了很大一部分能源，而膜分离有可能大大减少这种使用。了解吸附引起的沸石膜微观结构的变化将影响沸石膜的制备和利用。沸石膜具有分离有机异构体（结构异构体和立体异构体）和共沸物的潜力，并且这些能力与其高温稳定性相结合使其具有优于聚合物膜的显著优势。沸石层在储氢和微型器件中具有潜在的应用。预计膜技术专利的延续有可能通过商业化迅速和直接造福社会。 预计至少有一名学生将得到GAANN奖学金的支持，该奖学金将K-12和社区外展作为必需的方面之一。本科生将得到支持，一名高中生将参与这项研究，每年夏天。