Lee Wang-Geun, Yoon Tae-Ung, Bae Youn-Sang, Kim Kwang S, Baek Seung Bin
Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST) 50 UNIST-gil Ulsan 44919 Republic of Korea
Department of Chemical and Biomolecular Engineering, Yonsei University 50 Yonsei-ro, Seodaemun-gu Seoul 03722 Republic of Korea
RSC Adv. 2019 Nov 12;9(63):36808-36814. doi: 10.1039/c9ra08184d. eCollection 2019 Nov 11.
We have studied the adsorption properties of Xe and Kr in a highly microporous hydrogen-bonded organic framework based on 1,3,5-tris(4-carboxyphenyl)benzene, named HOF-BTB. HOF-BTB can reversibly adsorb both noble gases, and it shows a higher affinity for Xe than Kr. At 1 bar, the adsorption amounts of Xe were 3.37 mmol g and 2.01 mmol g at 273 K and 295 K, respectively. Ideal adsorbed solution theory (IAST) calculation predicts selective separation of Xe over Kr from an equimolar binary Xe/Kr mixture, and breakthrough experiments demonstrate the efficient separation of Xe from the Xe/Kr mixture under a dynamic flow condition. Consecutive breakthrough experiments with simple regeneration treatment at 298 K reveal that HOF-BTB would be an energy-saving adsorbent in an adsorptive separation process, which could be attributed to the relatively low isosteric heat ( ) of adsorption of Xe. The activated HOF-BTB is very stable in both water and aqueous acidic solutions for more than one month, and it also shows a well-preserved crystallinity and porosity upon water/acid treatment. Besides, HOF-BTB adsorbs about 30.5 wt%, the highest value for HOF materials, of water vapor during the adsorption-desorption cycles, with a 19% decrease in adsorption amounts of water vapor after five cycles.
我们研究了基于1,3,5-三（4-羧基苯基）苯的高度微孔氢键有机骨架（命名为HOF-BTB）对Xe和Kr的吸附特性。HOF-BTB可以可逆地吸附这两种稀有气体，并且它对Xe的亲和力高于Kr。在1 bar下，273 K和295 K时Xe的吸附量分别为3.37 mmol/g和2.01 mmol/g。理想吸附溶液理论（IAST）计算预测，从等摩尔二元Xe/Kr混合物中，Xe相对于Kr具有选择性分离，并且突破实验证明了在动态流动条件下从Xe/Kr混合物中有效分离Xe。在298 K下进行简单再生处理的连续突破实验表明，HOF-BTB在吸附分离过程中是一种节能吸附剂，这可能归因于Xe相对较低的等量吸附热（ ）。活化后的HOF-BTB在水和酸性水溶液中都非常稳定，超过一个月，并且在水/酸处理后也表现出良好的结晶度和孔隙率。此外，HOF-BTB在吸附-解吸循环中吸附约30.5 wt%的水蒸气，这是HOF材料中的最高值，五个循环后水蒸气吸附量下降19%。
