Small-pore zeolites have been a research hotspot in the field of gas adsorption and separation. Despite the high adsorption levels of these zeolites, the slow adsorption and desorption rate as well as desorption hysteresis are detrimental to the industrial applications. In this work, nano/micro-scale (∼500 nm) K-KFI zeolite crystals were synthesized via hydrothermal and ultrasound-assisted (US) methods. The US-K-KFI zeolites obtained were characterized by means of X-ray diffraction, scanning electron microscopy, and nitrogen adsorption-desorption isotherms at 77 K. The effect of the ultrasonic treatment time on zeolite formation was investigated. The results revealed that the ultrasonic time had a significant effect on the morphology of the K-KFI zeolite, and the particle size was reduced from 1.5 μm to 500 nm. Furthermore, the sample ultrasonically treated for 3 h and crystallized for 1 day (US-K-KFI-3h/1d) exhibited the same high level of crystallinity as the sample hydrothermally crystallized for 3 days without ultrasonic treatment (HT-K-KFI-0h/3d). Compared with large-crystal (3 μm) zeolite (HT-K-KFI-0h/3d) at a given pressure, nano/micro-scale (500 nm) zeolite (US-K-KFI-10h/1d) was characterized by a shorter adsorption equilibrium time and exhibited enhanced mass transfer due to its shorter diffusion path. Moreover, compared with that of HT-K-KFI-0h/3d, the adsorption capacity of US-K-KFI-10h/1d for CO₂, CH₄, N₂, and O₂ was 31%, 24%, 18%, and 26% higher, respectively, at room temperature (298 K) and 1 bar. The results of this work showed that the ultrasound-assisted method represents a rapid and controllable means of synthesizing nano/micro-scale zeolites.

小孔沸石一直是气体吸附和分离领域的研究热点。尽管这些沸石具有高吸附水平，但是缓慢的吸附和解吸速率以及解吸滞后现象不利于工业应用。在这项工作中，通过水热和超声辅助（US）方法合成了纳米/微米级（〜500 nm）K-KFI沸石晶体。通过X射线衍射，扫描电子显微镜和77 K下的氮吸附-解吸等温线对所得的US-K-KFI沸石进行了表征。研究了超声处理时间对沸石形成的影响。结果表明，超声时间对K-KFI沸石的形貌有显着影响，并且粒径从1.5μm减小到500 nm。此外，超声处理3小时并结晶1天的样品（US-K-KFI-3h / 1d）与未经超声处理水热结晶3天的样品（HT-K-KFI-0h / 3d）。与给定压力下的大晶体（3μm）沸石（HT-K-KFI-0h / 3d）相比，纳米/微米（500 nm）沸石（US-K-KFI-10h / 1d）的特征在于较短的吸附平衡时间，并由于其较短的扩散路径而表现出增强的传质。而且，与HT-K-KFI-0h / 3d相比，US-K-KFI-10h / 1d对CO的吸附容量 与给定压力下的大晶体（3μm）沸石（HT-K-KFI-0h / 3d）相比，纳米/微米（500 nm）沸石（US-K-KFI-10h / 1d）的特征在于较短的吸附平衡时间，并由于其较短的扩散路径而表现出增强的传质。而且，与HT-K-KFI-0h / 3d相比，US-K-KFI-10h / 1d对CO的吸附容量 与给定压力下的大晶体（3μm）沸石（HT-K-KFI-0h / 3d）相比，纳米/微米（500 nm）沸石（US-K-KFI-10h / 1d）的特征在于较短的吸附平衡时间，并由于其较短的扩散路径而表现出增强的传质。而且，与HT-K-KFI-0h / 3d相比，US-K-KFI-10h / 1d对CO的吸附容量₂，在室温（298 K）和1 bar下，CH ₄，N ₂和O ₂分别高31％，24％，18％和26％。这项工作的结果表明，超声辅助方法代表了一种合成纳米/微米级沸石的快速且可控的方法。