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Improved gel synthesis enables routes to Al-rich chabazite
Microporous and Mesoporous Materials ( IF 5.2 ) Pub Date : 2020-11-12 , DOI: 10.1016/j.micromeso.2020.110755
Anthony Vallace , Grant C. Kester , Chris Bongo , William Casteel , Garret Lau , Roger Whitley , Charles G. Coe

Phase pure Al-rich CHA(1.6–2.0) was prepared both from seed-assisted and non-seeded gel routes. Two different gel composition spaces were explored and both cation composition and the addition of seeds had a large effect on the product phase. A working hypothesis that guided the initial synthesis work is that the product phase and SAR is a strong function of the SiO2 solubility for the given gel system and addition of a seed would nucleate a CHA phase. Adsorption studies on pure and mixed alkali/alkaline earth CHA(2.0) showed homogeneous isosteric heats and low N2 Henry's constants for the pure Na and Li forms as well as Ca2Li8CHA(2.0); whereas a heterogenous heat and significant increase in Henry's constant were observed for higher Ca loadings in this mixed Ca/Li system. This behavior strongly suggests that in the dehydrated form, <2Ca/uc site inside the hexagonal prism of CHA, inaccessible to N2. This work shows the specific cation content of the phase pure, Al-rich CHA can be tailored to exhibit highly effective adsorbents for removing N2 from N2-containg streams.



中文翻译:

改进的凝胶合成可实现富铝菱沸石的途径

从种子辅助和非种子凝胶途径制备纯铝富相CHA(1.6-2.0)。探索了两种不同的凝胶组成空间,阳离子组成和种子的添加对产物相都有很大的影响。指导初始合成工作的一个可行假设是,产物相和SAR是给定凝胶系统的SiO 2溶解度的强函数,添加种子会成核CHA相。对纯碱金属和混合碱/碱土CHA(2.0)的吸附研究表明,纯Na和Li形式以及Ca 2 Li 8的均相等规热量和低N 2 Henry常数CHA(2.0); 而在这种混合的Ca / Li系统中,较高的Ca含量观察到异质热和Henry常数的显着增加。这种现象强烈表明,在脱水形式下,CHA六角棱柱内的<2Ca / uc位置不可接近N 2。这项工作表明,可以调整相中纯净,富铝的CHA的比阳离子含量,以显示出高效的吸附剂,从含N 2的物流中去除N 2

更新日期:2020-11-12
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