Ding Qi, Zhang Zhaoqiang, Yu Cong, Zhang Peixin, Wang Jun, Cui Xili, He Chao-Hong, Deng Shuguang, Xing Huabin
Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China.
Institute of Zhejiang University-Quzhou, 78 Jiuhua Boulevard North, Quzhou 324000, China.
Sci Adv. 2020 Apr 10;6(15):eaaz4322. doi: 10.1126/sciadv.aaz4322. eCollection 2020 Apr.
Physisorption is a promising technology to cut cost for separating ethylene (CH) from ethane (CH), the most energy-intensive separation process in the petrochemical industry. However, traditional thermodynamically selective adsorbents exhibit limited CH/CH selectivity due to their similar physiochemical properties, and the performance enhancement is typically at the expense of elevated adsorption heat. Here, we report highly-efficient CH/CH adsorption separation in a phosphate-anion pillared metal-organic framework ZnAtzPO exploiting the equilibrium-kinetic synergetic effect. The periodically expanded and contracted aperture decorated with electronegative groups within ZnAtzPO enables effective trapping of CH and impedes the diffusion of CH, offering an extraordinary equilibrium-kinetic combined selectivity of 32.4. The adsorption heat of CH on ZnAtzPO (17.3 to 30.0 kJ mol) is substantially lower than many thermodynamically selective adsorbents because its separation capability only partially relies on thermodynamics. The separation mechanism was explored by computational simulations, and breakthrough experiments confirmed the excellent CH/CH separation performance of ZnAtzPO.
物理吸附是一种很有前景的技术，可降低从乙烷（C₂H₆）中分离乙烯（C₂H₄）的成本，这是石化行业中能源密集度最高的分离过程。然而，传统的热力学选择性吸附剂由于其相似的物理化学性质，表现出有限的C₂H₄/C₂H₆选择性，而且性能的提高通常是以吸附热升高为代价的。在此，我们报道了在一种磷酸根阴离子柱撑金属有机框架ZnAtzPO中利用平衡-动力学协同效应实现高效的C₂H₄/C₂H₆吸附分离。ZnAtzPO内带有电负性基团的周期性扩张和收缩的孔径能够有效地捕获C₂H₄并阻碍C₂H₆的扩散，提供了高达32.4的非凡的平衡-动力学综合选择性。C₂H₄在ZnAtzPO上的吸附热（17.3至30.0 kJ mol⁻¹）大大低于许多热力学选择性吸附剂，因为其分离能力仅部分依赖于热力学。通过计算模拟探索了分离机理，突破实验证实了ZnAtzPO优异的C₂H₄/C₂H₆分离性能。
