Metal organic frameworks (MOFs) with appropriate pore size and sufficient CO 2 -philic groups are required to improve the mixed matrix membranes (MMMs)-based CO 2 capture. Herein, NH 2 -CPL-1 is designed for capture by utilizing amino pyrazine instead of pyrazine in CPL-1. The introduced CO 2 -philic amino groups together with rich hydroxyl and carboxyl groups in CPL-1 could improve the selective adsorption of CO 2 , enhancing the solubility selectivity. At the meantime, after the introduction of amino-functional, the pore size of NH 2 -CPL-1 is decreased from 0.93 nm of CPL-1 to 0.85 nm, which is beneficial for the screening of CO 2 over N 2 . As a result, the CO 2 separation performances of MMMs could be promoted greatly under the action of NH 2 -CPL-1. MMM with NH 2 -CPL-1 of 10 wt.% exhibited the best CO 2 separation performance, with CO 2 /N 2 selectivity of 85 and CO 2 permeability of 104 Barrer at 25 °C and 0.4 MPa. Compared with the CPL-1/Pebax-10 wt.% MMM, it was increased by 9.5 % and 13.3 %, respectively. This satisfactory CO 2 separation performance surpasses those of most reported other MOFs based MMMs, which is attributed to the facilitated CO 2 transport and pore size screening from the introduced amino groups. This is also confirmed by the improvement of diffusion selectivity and solution selectivity. The proposed NH 2 -CPL-1 shows great prospect as filler for enhanced MMMs-based CO 2 capture.
In this work, metal-organic framework compound CPL-1 of a formula {[Cu 2 (pzdc) 2 (pyz)]⋅2H 2 O} n (pzdc = pyrazine-2,3-dicarboxylate, pyz = pyrazine) possessing kinetic quantum sieving effect on H 2 /D 2 separation was selected to prepare two new chromatography stationary phase materials CPL-1@γ-Al 2 O 3 and MnCl 2 @CPL-1@γ-Al 2 O 3 by loading CPL-1 on γ-Al 2 O 3 particles with size 80–100 mesh through repeating in situ crystallization process , and afterwards by loading MnCl 2 on CPL-1@γ-Al 2 O 3 via impregnation approach. The two optimized materials were thoroughly characterized by IR, XRD , SEM, EDS and TG/DTA method. The experimental results showed that, under liquid nitrogen temperature by using just 1-m chromatographic column and cheap He gas as carrier gas, the MnCl 2 @CPL-1@γ-Al 2 O 3 can solve the problem of long separation time and trailing phenomenon existing in the CPL-1@γ-Al 2 O 3 column, can realize highly effective hydrogen isotope H 2 /D 2 separation with good separation resolution (R = 1.62) and approximate Gauss distribution of chromatographic peak, can be used for both qualitative and quantitative analysis of hydrogen isotope H 2 /D 2 with short separation time of 6.5 min.
Yan Zhang,Zhonghang Chen,Xing Liu,Ze Dong,Peixin Zhang,Jun Wang,Qiang Deng,Zheling Zeng,Shuhua Zhang,Shuguang Deng
Removal of trace SO2 contaminants from gas mixtures by the molecular sieving effect is highly desired. Herein, a microporous metal–organic framework Cu2(pzdc)2(pyz) [CPL-1, pzdc = 2,3-pyrazinedicarboxylate; pyz = pyrazine] with a dumbbell-shaped 1D channel and specific binding sites is explored for deep desulfurization. The proper size of 4.1 × 6.2 Å and strong SO2 trapping sites on CPL-1 render a high adsorption uptake of SO2 (44.8 cm3 g–1) with a record-high selectivity for SO2/N2 (368) and SO2/CH4 (74.3) separation under ambient conditions. Moreover, the dispersion-corrected density functional theory calculations have identified the dual specific adsorption sites of SO2, such as Sδ+···Oδ− electrostatic interactions and Oδ−···Hδ+ hydrogen bonds. The feasibility of CPL-1 for SO2/N2, SO2/CH4, CO2/CH4, CO2/N2, and mimicked flue gas mixture separations was validated by dynamic breakthrough experiments. Water vapor and CO2 impurity were introduced to the gas feed streams to confirm the excellent separation performance of CPL-1. Moreover, a scale-up production of CPL-1 via a facile and green method was conducted, and a reproducible CPL-1 adsorbent with undamaged adsorption and separation performances was successfully manufactured in kilogram quantity. These unique features render CPL-1 a very promising adsorbent for practical desulfurization processes.