Amino-Functionalized Microporous MOFs for Capturing Greenhouse Gases CF₄ and NF₃ with Record Selectivity

Abstract

The capture and separation of fluorinated gases (F-gases) from N2 has the potential to not only reduce greenhouse gas emissions but also provide economic benefits for the semiconductor industry. In this work, two Ni-based metal–organic frameworks (MOFs), Ni-MOF (Ni­(ina)2, ina = isonicotinic acid) and amine-functionalized NH 2 –Ni-MOF (Ni­(3-ain)2, 3-ain = 3-aminoisonicotinic acid), were constructed for capturing F-gases (CF4 and NF3). At ambient conditions, both materials exhibit very high CF4 sorption capacities (2.92 mmol g–1 for Ni-MOF and 2.69 mmol g–1 for NH 2 –Ni-MOF). In addition, NH 2 –Ni-MOF exhibited a record selectivity of 46.3 for the CF4/N2 mixture at 298 K and 100 kPa, surpassing all benchmark adsorbents, including Ni-MOF (34.7). The kinetic adsorption tests demonstrated that Ni-MOF and NH 2 –Ni-MOF performed well for CF4/N2 and NF3/N2 mixtures. According to grand canonical Monte Carlo (GCMC) simulations, CF4 or NF3 interacts with NH 2 –Ni-MOF by multiple van der Waals interactions, resulting in stronger interaction than N2. More importantly, dynamic breakthrough experiments verified the practical separation potential of the two materials for CF4/N2 and NF3/N2 mixtures.

Ameliorating Adsorption Performance for Poisonous Methylene Blue through the Amino Functionalization of Metal–Organic Frameworks

“…Yang and co-workers reported the Ni-MOF and NH 2 -Ni-MOF in gas-phase adsorption ground selective adsorption performance. It was found that the pore size of NH 2 -Ni-MOF was smaller than that of Ni-MOF due to the modified −NH 2 , indicating that amino-functionalized groups significantly affect CF 4 /N 2 selectivity . In addition, differences in the adsorption behavior of pristine and NH 2 -functionalized MOFs on toxic dye molecules have also been investigated in previous reports.…”

“…37 NH 2 -Ni-MOF was smaller than that of Ni-MOF due to the modified −NH 2 , indicating that amino-functionalized groups significantly affect CF 4 /N 2 selectivity. 38 In addition, differences in the adsorption behavior of pristine and NH 2 -functionalized MOFs on toxic dye molecules have also been investigated in previous reports. It was reported that NH 2 -MIL-53(Al) has a higher adsorption capacity than MIL-53(Al) due to the hydrogen bonding interaction.…”

A Structured Ultramicroporous Metal‐Organic Framework for Carbon Dioxide Capture†

“…Porous coordination polymers (PCPs), also named metal‐organic frameworks (MOFs), show a large specific surface area, abundant and adjustable pore size, and diverse structures, which make them widely studied in many fields, especially for gas adsorption and separation. [ 14‐22 ] Various CO 2 capture and separation methods based on MOFs have been reported. [ 6,23‐25 ] It is imperative to consider issues such as high‐pressure drops, pipe clogging, and dust contamination when using MOFs in the large‐scale chemistry industry.…”

Theoretical Design of MOFs and PSA Process for Efficient Separation of CF4/NF3

“…Therefore, systematic studies on the CF 4 /NF 3 mixture separation performance of various MOFs by computational chemistry is an efficient and promising way to solve the existing CF 4 /NF 3 separation issues. Wang et al successfully synthesized Ni-MOFs and NH 2 -Ni-MOFs by experiments and highlighted that −NH 2 -functionalized MOF exhibits excellent adsorption performance for CF 4 and NF 3 , indicating that MOF materials possess great potential in separating CF 4 and NF 3 . The separation of CF 4 /NF 3 by physical adsorption using MOFs as an adsorbent is beneficial to the adsorbent regeneration.…”

“…Therefore, systematic studies on the CF 4 /NF 3 mixture separation performance of various MOFs by computational chemistry is an efficient and promising way to solve the existing CF 4 /NF 3 separation issues. Wang et al 24 The separation of CF 4 /NF 3 by physical adsorption using MOFs as an adsorbent is beneficial to the adsorbent regeneration. Moreover, the advantages of flexible processing capacity, simple equipment, no byproducts, and high automation make it widely used in the field of gas separation.…”