A stable ultramicroporous Cd(II)-MOF with accessible oxygen sites for efficient separation of light hydrocarbons with high methane production

作者：Xing-Zhe Guo, Bingwen Li, Guangzu Xiong, Bing Lin, Liu-Cheng Gui, Xiaoxia Zhang, Zhihui Qiu, Rajamani Krishna, Xinfang Wang, Xin Yan, Shui-Sheng Chen · 发表于：Separation and Purification Technology · 年份：2023 · DOI：10.1016/j.seppur.2023.125987 · 被引用次数：36 · 研究领域：Metal-Organic Frameworks: Synthesis and Applications、Catalytic Processes in Materials Science、Carbon dioxide utilization in catalysis

Metal-organic frameworks (MOFs) have garnered increasing attention for their effective separation of light hydrocarbons owing to their prominent separation selectivity and energy-efficient adsorption process. Here, we constructed a robust stable ultramicroporous Cd(II)-MOF ([Cd 5 (NTA) 4 (H 2 O) 2 ] (Me 2 NH 2 + ) 2 ·10H 2 O ( 1 )) with abundant accessible oxygen sites and investigated its adsorption performance for recovering high-purity methane (CH 4 ) from natural gas (NG) including C 1 (CH 4 )/C 2 (C 2 H 6 )/C 3 (C 3 H 8 ) mixtures. At ambient conditions, the theoretical equilibrium separation selectivity of 1 for C 2 H 6 /CH 4 (v/v = 10/85) and C 3 H 8 /CH 4 (v/v = 5/85) were found to be 34.3 and 223.8, respectively. The CH 4 /C 2 H 6 /C 3 H 8 (v/v/v = 85/10/5) mixture breakthrough experiments for 1 , conducted at 298 K, demonstrated effective separation performance with breakthrough times of up to 136 and 280 min·g −1 for C 2 H 6 and C 3 H 8 . Particularly, the CH 4 productivity (purity > 99.9 %) with 9.8 mmol·g −1 ranked the third in reported literatures, lower to the reported maximum value of 13.28 mmol·g −1 for Ni(TMBDC)(DABCO) 0.5 . Furthermore, Grand Canonical Monte Carlo (GCMC) simulations and first-principles density functional theory (DFT) calculations revealed that the high uptake and selectivity for C 3 H 8 and C 2 H 6 can be attributed to the abundant oxygen sites present in the pores. The dynamic breakthrough experiments comprehensively demonstrated that the...