Integrating Self-Partitioned Pore Space and Amine Functionality into an Aromatic-Rich Coordination Framework with Ph Stability for Effective Purification of C₂ Hydrocarbons

Abstract

A great demand for high-purity C2 hydrocarbons calls for the development of chemically stable porous materials for the effective isolation of C2 hydrocarbons from CH4 and CO2. However, such separations are challenged by their similar physiochemical parameters and have not been systematically studied to date. In this work, we reported a cadmium-based rod-packing coordination framework compound ZJNU-140 of a new 5,6,7-c topology built up from a custom-designed tricarboxylate ligand. The metal–organic framework (MOF) features an aromatic-abundant pore surface, uncoordinated amine functionality, and self-partitioned pore space of suitable size. These structural characteristics act synergistically to provide the MOF with both selective recognition ability and the confinement effect toward C2 hydrocarbons. As a result, the MOF displays promising potential for adsorptive separation of C2–CH4 and C2–CO2 mixtures. The IAST-predicted C2/CH4 and C2/CO2 adsorption selectivities, respectively, fall in the ranges of 7.3–10.2 and 2.1–2.9 at 298 K and 109 kPa. The real separation performance was also confirmed by dynamic breakthrough experiments. In addition, the MOF can maintain skeleton intactness in aqueous solutions with a wide pH range of 3–11, as confirmed by powder X-ray diffraction (PXRD) and isotherm measurements, showing no loss of framework integrity and porosity. The excellent hydrostability, considerable uptake capacity, impressive adsorption selectivity, and mild regeneration make ZJNU-140 a promising adsorbent material applied for the separation and purification of C2 hydrocarbons.

One Co-MOF with F Active Sites for Separation of C2H2 from CO2, C2H4, and CH4

“…The calculated BET and Langmuir surface areas were 509.1 and 572.7 m 2 g –1 , respectively (Figure S4). And the measured accessible pore volume of 0.237 cm 3 g –1 is lower than the theoretical value of 0.414 cm 3 g –1 calculated from the crystal data. The pore size distribution of 1a calculated by density functional theory (DFT) ranges from 5.4 to 6.5 Å, matching the results from the single crystal structure analysis.…”

Creating an Ethane Trap in a Ketone-Decorated MOF for One-Step Ethylene Separation from C2 Hydrocarbons

“…The BET values were higher than those of ZJNU-130 (228/251 m 2 g −1 ), 21 and were lower than those of ZJNU-132 (753/811 m 2 g −1 ), 21 ZJNU-133 (790 and 839 m 2 g −1 ), 22 ZJNU-140 (1051 and 1193 m 2 g −1 ). 23 In addition, a pore-size distribution ranging from 4 Å to 6 Å (Figure 2a) could be derived from the adsorption isotherm of the CO 2 at 195 K, based on the Horvath−Kawazoe model, which agreed well with the crystal structure. Following the gas adsorption experiment, the powder X-ray diffraction (PXRD) data of the activated NTUniv-63 was also checked, which overlapped well with the simulated and synthesized patterns (see Figure S1 in the Supporting Information).…”

“…The BET surface area and Langmuir surface area of NTUniv-63 were evaluated to be ∼518 m 2 g –1 and 565 m 2 g –1 , respectively. The BET values were higher than those of ZJNU-130 (228/251 m 2 g –1 ), and were lower than those of ZJNU-132 (753/811 m 2 g –1 ), ZJNU-133 (790 and 839 m 2 g –1 ), ZJNU-140 (1051 and 1193 m 2 g –1 ) . In addition, a pore-size distribution ranging from 4 Å to 6 Å (Figure a) could be derived from the adsorption isotherm of the CO 2 at 195 K, based on the Horvath–Kawazoe model, which agreed well with the crystal structure.…”

pH-Stable Zn(II) Coordination Polymer as a Multiresponsive Turn-On and Turn-Off Fluorescent Sensor for Aqueous Medium Detection of Al(III) and Cr(VI) Oxo-Anions

“…In this context, coordination polymers (CPs) and/or metal–organic frameworks (MOFs) are attracting immense interest due to their intriguing properties, such as an accessible high surface area, ordered crystalline structure, permanent porosity, functional tunability, structural diversity, unique flexibility, and variable morphologies. − In particular, owing to the presence of well-organized chromophores (Lewis acid and basic sites) in their chemically tailorable framework, CPs/MOFs exhibit excellent luminescent properties. ,, Such superior properties make them fascinating as an effective sensing probe for the detection of variable analytes including toxic metal ions, hazardous anions, explosives, antibiotics, pesticides, and small organic molecules. ,,− Moreover, the specific host–guest interactions between the incoming analytes and the accessible functional groups of the framework bring more advantages in terms of easy operability, fast responsivity, high selectivity, good sensitivity, and multiple recyclabilities . − Taking advantage of such superiorities, although a large number of CPs/MOFs have been explored for the rapid detection of toxic metal cations and noxious oxo-anions individually or combinedly having turn-off luminescence only, ,,,, multiresponsive behavior with one turn-off and another turn-on luminescent detection by a single CP/MOF platform remains unexplored so far. Compared to single-analyte recognition, frameworks showing simultaneous and rapid sensing for multiple analytes are highly desirable and on-demand as they can increase the versatility and multipurpose usage possibility of the developed sensory materials. ,− On the other hand, although a decent number of coordination frameworks have displayed excellent luminescent performance with high sensitivity and selectivity, their insufficient hydrolytic stability, as well as chemical instability, , forced them to detect targeted analytes in a nonaqueous medium. , However, to make the developed framework affordable and easy to handle, it is desirable to develop robust sensor materials that ca...…”