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CO 2 capture using ZIF-8 /water-glycol-2-methylimidazole slurry with high capacity and low desorption heat
Chemical Engineering Science ( IF 4.7 ) Pub Date : 2018-06-01 , DOI: 10.1016/j.ces.2018.02.022
Hai Li , Wan Chen , Bei Liu , Chongzhi Jia , Zhichao Qiao , Changyu Sun , Lanying Yang , Qinglan Ma , Guangjin Chen

Abstract By dispersing zeolitic imidazolate framework-8 (ZIF-8) in different liquids composed of water, glycol, and 2-methylimidazole (mIm), a series of ZIF-8/water-glycol-mIm slurries were formed. The sorption isotherms of CO2 in these slurries, as well as in aqueous solution of mIm, were measured in the temperature range from 293.15 to 313.15 K. Next, the enthalpies of CO2 sorption in these slurries were correspondingly determined using the Clausius-Clapeyron equation. At the same time, the sorption kinetics and regeneration performances of the slurries were investigated. The results show that CO2 absorption in aqueous mIm solutions is dominated by chemical absorption, while in the ZIF-8/mIm-water-glycol slurry, CO2 uptake is determined by both chemical absorption and physical adsorption. Increasing ZIF-8 content in slurry can significantly increase the sorption capacity and decrease the sorption heat by increasing the physical adsorption contribution. Increasing ZIF-8 content can even increase the sorption rate within a certain content range. Although the presence of glycol decreases the sorption capacity and increases viscosity to a certain extent, it also significantly decreases the desorption heat. By considering sorption capacity, desorption heat, and viscosity, a particular ZIF-8 slurry recipe, i.e., solid fraction of 15–25.0 wt% and liquid composition of approximately mIm 25 wt% + water 40 wt% + glycol 35 wt%, is recommended, for which the CO2 sorption capacity can reach 1.6 mol/L (higher than that of some alkanol amine solutions) under ambient pressure and 313.15 K, while the desorption heat could be as low as 32 kJ/mol. The structure of ZIF-8 can remain intact in the CO2 capture process in the presence of mIm, i.e., the slurry could be regenerated perfectly.

中文翻译:

使用具有高容量和低解吸热的 ZIF-8 /水-乙二醇-2-甲基咪唑浆液捕获 CO 2

摘要 通过将沸石咪唑骨架-8 (ZIF-8) 分散在由水、乙二醇和2-甲基咪唑(mIm) 组成的不同液体中,形成了一系列ZIF-8/水-乙二醇-mIm 浆料。在 293.15 到 313.15 K 的温度范围内测量了这些浆液以及 mIm 水溶液中 CO2 的吸附等温线。接下来,使用克劳修斯-克拉珀龙方程相应地确定了这些浆液中 CO2 吸附的焓。同时,研究了浆料的吸附动力学和再生性能。结果表明,mIm 水溶液中的 CO2 吸收以化学吸收为主,而在 ZIF-8/mIm-水-乙二醇浆液中,CO2 吸收由化学吸收和物理吸附共同决定。增加浆料中ZIF-8的含量可以通过增加物理吸附贡献来显着提高吸附容量并降低吸附热。增加ZIF-8含量甚至可以在一定含量范围内提高吸附率。尽管乙二醇的存在在一定程度上降低了吸附能力并增加了粘度,但它也显着降低了解吸热。通过考虑吸附能力、解吸热和粘度,特定的 ZIF-8 浆液配方,即 15-25.0 wt% 的固体分数和大约 mIm 25 wt% + 水 40 wt% + 乙二醇 35 wt% 的液体组成,是推荐使用,在常压和313.15 K的条件下,CO2吸附能力可达1.6 mol/L(高于某些烷醇胺溶液),而解吸热可低至32 kJ/mol。
更新日期:2018-06-01
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