Optimized Synthetic Strategies, Structures, Properties and Modification of Open Framework Oxides with High Ion Exchange Capacity

高离子交换容量开放骨架氧化物的优化合成策略、结构、性能及改性

• 批准号: 0095633
• 负责人: John Parise
• 金额: $ 43.91万
• 依托单位: SUNY at Stony Brook
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-03-01 至 2004-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0095633&HistoricalAwards=false
• 关键词: Optimized; Synthetic; Strategies; Structures; Properties

This project focuses on microporous and zeolitic materials with negatively charged frameworks, regularly spaced pores and channels of molecular dimension that possess cation-exchange properties that can sometimes discriminate between ions and/or gases based upon size and shape. Apart from formulating strategies for the discovery of new materials with these characteristics, it is important to understand the structural basis for any selectivity. Recent structural results, obtained using synchrotron radiation, suggest strategies to increase ion exchange capacity. It is hypothesized that low valent metals can replace common higher valent ones in framework structures, lithium for silicon for example, thereby producing highly negatively charged frameworks with enhanced ion exchange capacity and selectivity. The crystal chemistry of lithium makes it ideal in this regard and investigations of several new lithosilicates indicate a rich structural chemistry. Syntheses to expand the range of materials with Li in the framework will be pursued, including attempts to tailor the exchange properties of "pure" silica and aluminosilicate molecular sieves. This will be coupled with studies of the relationships between the sorbtive and catalytic properties of these new materials. An extension of Li-substitution into tetrahedral networks is the substitution of Na into octahedral networks. This effectively lowers the cationic charge on the framework and increases the number of extraframework cations and so ion exchange capacity. The structure of the first example of this synthetic philosophy is an Octahedral Molecular Sieves (OMS) based on the chemistry Na4[Na8Nb12.8Ti3.2]O44.8(OH)3.2o8H2O. We are planning to expand the catalogue of such materials and to seek the structural basis for their selectivity toward strontium. These classes of materials are potentially useful in separation, contaminant removal and sequestration applications. They are important to environmental technologies that improve remediation and mitigation, and decrease future cleanup costs by emphasizing pollution avoidance and novel approaches to the measurement, assessment, and feedback for the optimization of pollution avoidance and prevention. It will also impact industrial ecology by providing materials that can be applied to improve manufacturing processes and their environmental impact. Students trained in these areas of high-technology will likely be very competitive in the future job market.

该项目的重点是微孔和沸石材料，具有带负电荷的框架，规则间隔的孔和分子尺寸的通道，具有阳离子交换性能，有时可以根据大小和形状区分离子和/或气体。除了制定发现具有这些特征的新材料的策略外，重要的是要了解任何选择性的结构基础。 最近的结构结果，使用同步辐射，建议战略，以增加离子交换能力。 据推测，低价金属可以取代骨架结构中常见的高价金属，例如锂取代硅，从而产生具有增强的离子交换能力和选择性的高度带负电荷的骨架。 锂的晶体化学使其成为这方面的理想材料，对几种新的石硅酸盐的研究表明了丰富的结构化学。将追求合成以扩大在框架中具有Li的材料的范围，包括尝试定制“纯”二氧化硅和铝硅酸盐分子筛的交换性质。这将与这些新材料的吸附和催化性能之间的关系的研究相结合。 Li取代到四面体网络中的扩展是Na取代到八面体网络中。 这有效地降低了骨架上的阳离子电荷，并增加了骨架外阳离子的数量，从而增加了离子交换能力。 这种合成原理的第一个例子的结构是基于化学结构Na 4 [Na8Nb12.8Ti3.2]O44.8（OH）3.2o8H2O的八面体分子筛（OMS）。 我们正计划扩大这类材料的目录，并寻找它们对锶的选择性的结构基础。这些种类的材料在分离、污染物去除和螯合应用中是潜在有用的。它们对环境技术很重要，这些技术通过强调污染避免和新的测量、评估和反馈方法来优化污染避免和预防，从而改善补救和缓解，并降低未来的清理成本。 它还将通过提供可用于改善制造工艺及其环境影响的材料来影响工业生态。在这些高科技领域受过训练的学生在未来的就业市场上可能会非常有竞争力。