Development of Functional Adsorbent for Air Separation by Addition of Metal Cluster Ion into Zeolites

吸附法是一种有效的空气分离制氧方法。近年来，人们对高性能吸附剂的需求越来越大，以降低成本和能耗。本研究基于表面分析（光谱学和热力学分析等）对沸石吸附剂进行了改性，开发了一种高效的空气分离吸附剂。本文的研究结果总结如下：1。金属离子簇离子对沸石表面的改性。为了提高N_2选择性吸附位点的数量，制备了Li-CuLSX和Li-Ag-LSX。即在低硅X沸石（LSX沸石）的钠笼和/或D6R中形成Ag和Cu离子簇，以物理阻塞无效的阳离子位（- i位），并将Li^+离子交换到簇离子还原产生的新阳离子位上，以制备稳定的高表面积吸附剂，优化了制备条件。金属离子簇的表面分析包括LSX沸石。为了分析Li-CuLSX和Li-Ag-LSX的表面性质，以CO和CH_4为吸附探针分子，利用红外光谱研究了它们的吸附位点特征。Li-CuLSX对CO的吸附量是Li-LSX的3倍左右。结果表明，通过簇离子掺杂的方法，Li^+离子被选择性地交换到III位。此外，甲烷吸附表明，III位的静电场比Li-LSX强。这种现象可能是由于D6R和/或钠盐笼中存在铜簇离子的影响。Li-CuLSX对N_2和O_2的吸附和空气分离特性。对不同吸附剂的气体吸收和分离特性进行了定量分析。在211K时，Li-CuLSX的空气分离系数大于Li-LSX。

An adsorption method is one of the effective air separation processes to oxygen produce. Recently, the high-performance adsorbent is strongly required for cost and energy reduction. In this study, to develop a high performance adsorbent for air separation, zeolite adsorbents were modified based on the surface analyses (spectroscopy and thermodynamic analyses etc.). The result obtained in this work is summarized as follows.1.Modification of zeolite surface using metal ion cluster ions.To enhance the amount of N_2 selective adsorption site, Li-CuLSX and Li-Ag-LSX were prepared. Namely, Ag and Cu ion clusters were formed in sodalite cage and/or D6R of low silica X zeolite (LSX zeolite) in order to block ineffective cationic sites (site-I) physically, and Li^+ ions were exchanged into new cation sites created by reduction of the cluster ions, To prepare stable adsorbents with high surface area, the preparing condition were optimized.2.Surface analysis of metal ion cluster included LSX zeolites.In order to analyze surface properties of Li-CuLSX and Li-Ag-LSX, the characteristics of adsorption sites were studied by infrared spectroscopy using CO and CH_4 as adsorption probe molecules. Amount of CO adsorption on Li-CuLSX enhanced to about 3 times than that on Li-LSX. The result showed that Li^+ ions were selectively exchanged to site III using the cluster ion doping method. Furthermore, the methane adsorption showed that the electrostatic field of site III was stronger than that of Li-LSX. This phenomenon may be attributed to an effect of copper cluster ions existed in D6R and/or sodalite cage.3.N_2 and O_2 adsorption and air separation characters of Li-CuLSX.The quantitative analyses of gas absorption and separation characteristics for various adsorbents were carried out. At 211K, air separation factor of Li-CuLSX is larger than that of Li-LSX.