Denning Shurraya, Majid Ahmad Aa, Lucero Jolie M, Crawford James M, Carreon Moises A, Koh Carolyn A
Chemical and Biological Engineering Department, Colorado School of Mines, Golden, Colorado 80401, United States.
ACS Appl Mater Interfaces. 2020 Nov 25;12(47):53510-53518. doi: 10.1021/acsami.0c15675. Epub 2020 Nov 13.
The large demand of natural gas consumption requires an effective technology to purify and store methane, the main component of natural gas. Metal-organic frameworks and gas hydrates are highly appealing materials for the efficient storage of industrially relevant gases, including methane. In this study, the methane storage capacity of the combination of methane hydrates and HKUST-1, a copper-based metal-organic framework, was studied using high pressure differential scanning calorimetry. The results show a synergistic effect, as the addition of HKUST-1 promoted hydrate growth, thus increasing the amount of water converted to hydrate from 5.9 to 87.2% and the amount of methane stored, relative to the amount of water present, from 0.55 to 8.1 mmol/g. The success of HKUST-1 as a promoter stems mainly from its large surface area, high thermal conductivity, and hydrophilicity. These distinctive properties led to a kinetically favorable decrease in hydrate growth induction period by 4.4 h upon the addition of HKUST-1. Powder X-ray diffraction and nitrogen isotherm suggests that the hydrate formation occurs primarily on the surface of HKUST-1 rather than within the pores. Remarkably, the HKUST-1 crystals show no significant changes in terms of structural integrity after many cycles of hydrate formation and dissociation, which results in the material having a long life cycle. These results confirm the beneficial role of HKUST-1 as a promoter for gas hydrate formation to increase methane gas storage capacity.
对天然气消费的巨大需求需要一种有效的技术来净化和储存天然气的主要成分甲烷。金属有机框架材料和气体水合物是用于高效储存包括甲烷在内的工业相关气体的极具吸引力的材料。在本研究中，使用高压差示扫描量热法研究了甲烷水合物与铜基金属有机框架HKUST-1组合的甲烷储存能力。结果显示出协同效应，因为添加HKUST-1促进了水合物的生长，从而使转化为水合物的水量从5.9%增加到87.2%，相对于存在的水量，储存的甲烷量从0.55 mmol/g增加到8.1 mmol/g。HKUST-1作为促进剂的成功主要源于其大表面积、高导热性和亲水性。这些独特的性质使得添加HKUST-1后水合物生长诱导期在动力学上有利地缩短了4.4小时。粉末X射线衍射和氮气等温线表明水合物形成主要发生在HKUST-1的表面而非孔内。值得注意的是，HKUST-1晶体在经过多次水合物形成和解离循环后，在结构完整性方面没有显著变化，这使得该材料具有较长的生命周期。这些结果证实了HKUST-1作为促进气体水合物形成以增加甲烷气体储存能力的有益作用。
