Extraordinary Separation of Acetylene-Containing Mixtures in a Honeycomb Calcium-Based MOF with Multiple Active Sites

Abstract

Acetylene (C2H2) separation from multicomponent mixtures is vitally important but industrially challenging for the collection of high-purity C2H2. To address this requirement, the reaction between the alkaline-earth Ca2+ ions with a dicarboxylate-diazolate linker, 4,6-di(1H-tetrazol-5-yl)isophthalic acid (H4dtzip), gave rise to a new metal–organic framework (MOF) material [Ca(dtzip)0.5H2O]·2H2O (1). The material presents unique regular tubular channels based on threefolded helical rod-like secondary building units with rich open metal sites and exposed organic hydrogen-bonding N/O acceptors that enhance the interactions with C2H2 molecules, endowing significant selectivity for C2H2 over C2H4 (5.4), C2H6 (5.6), CH4 (30.0), and CO2 (7.7) at 298 K and 100 kPa. Column breakthrough experiments confirmed the extraordinary C2H2 separation performance of the material with the separation time intervals in the range of 18–24 min g–1 for binary (C2H2–C2H4, C2H2–C2H6, C2H2–CO2, and C2H2–CH4) or ternary (C2H2–C2H4–C2H6 and C2H2–C2H4–CO2) gas mixtures under dynamic conditions.

Discriminatory Gate‐Opening Effect in a Flexible Metal–Organic Framework for Inverse CO2/C2H2 Separation

“…Strikingly, the Q st subsequently increased to 51.8 kJ mol ‐1 with saturated adsorption. Moreover, the initial Q st value (43.1 kJ mol ‐1 ) exceeded those of most reported top‐performance CO 2 ‐selective MOFs (Table S2, Supporting Information; Figure 2f), [ 22 ] such as MUF‐16 (32.3 kJ mol −1 ), [ 23 ] PCP‐NH 2 ‐ipa (36.6 kJ mol −1 ), [ 24 ] SU‐101(Ga) (31.3 kJ mol −1 ), [ 25 ] Cu‐F‐pymo‐b (29.0 kJ mol −1 ), [ 26 ] Zn‐F‐DATRZ (24.9 kJ mol −1 ), [ 27 ] Ce(IV)‐MIL‐140‐4F (39.5 kJ mol −1 ), [ 28 ] Zn(atz)(BDC‐Cl4) 0.5 (32.7 kJ mol −1 ), [ 29 ] [Zn(odip) 0.5 (bpe) 0.5 (CH 3 OH)]·0.5NMF·H 2 O (42.3 kJ mol −1 ), [ 30 ] and Mn(bdc)(dpe) (29 kJ mol −1 ). [ 17 ] Notably, consistent with those MOFs with low Q st (< 30 kJ mol −1 ) for CO 2 , Zn‐DPNA can be easily regenerated between adsorption and desorption cycles without more activation processes, supporting a lower regeneration energy requirement.…”

Two Chemorobust Cobalt(II) Organic Frameworks as High Sensitivity and Selectivity Sensors for Efficient Detection of 3-Nitrotyrosine Biomarker in Serum

“…Numerous studies have declared metal–organic frameworks (MOFs) showing great potential as sensors for detecting toxic heavy metal ions/anions, hazardous chemicals, volatile organic compounds (VOCs), or even bioactive molecules, which can be attributed to the unique structural features of various architectures, large specific surface area, and easily modified confined space. − It is noteworthy that MOF-based sensors displayed highly sensitive and rapid detection abilities in sensing nitro-containing analytes, from the aromatic explosives of trinitrotoluene (TNT)/picric acid (TNP) to the nitroimidazole/nitrofuran antibiotics, owing to the electron-withdrawing nitro groups. − From this point of view, designing efficient and sensitive MOF-based 3-NT sensors is technically feasible. Recently, Wang and co-workers designed two LMOFs through a mixed-ligands strategy and then evaluated their luminescence sensing performances in detecting 3-NT in water. , Biswas’s group also designed a water-stable HfMOF and used it for 3-NT sensing in HEPES solution .…”

Highly Efficient Propyne/Propylene Separation in a “Flexible-Robust” and Hydrolytically Stable Cu(II)-MOF

“…Propylene (C 3 H 6 ) is widely used in the production of various chemicals and is mostly produced from the cracking of large hydrocarbon molecules or crude oil in the petrochemical industry, during which propyne (C 3 H 4 ) and propane (C 3 H 8 ) are always produced as undesirable byproducts . The highly efficient removal of C 3 H 4 or C 3 H 8 from the C 3 H 4 /C 3 H 6 or C 3 H 6 /C 3 H 8 mixture is of high importance but challenging because of the similar boiling points and molecular sizes of the three hydrocarbons. , Therefore, many studies have been devoted to exploring more effective C 3 H 6 purification technologies. , Compared with traditional gas separation methods (cryogenic distillation or catalytic partial hydrogenation), a physical adsorption method based on porous materials is regarded to be environmentally friendly and energy efficient. − Metal–organic frameworks (MOFs) − consisting of metal centers/clusters and organic ligands have emerged as a type of unique porous material in the past two decades − and widely explored for gas separation − owing to their advantages, including structural diversity, adjustable pore size, and designable adsorption sites. ,, …”