Simultaneously Enhanced Hydrophilicity and Stability of a Metal‐Organic Framework via Post‐Synthetic Modification for Water Vapor Sorption/Desorption

Abstract

With increasing demands for high-performance water sorption materials, metal-organic frameworks (MOFs) have gained considerable attention due to their high maximum uptake capacities. In many cases, however, high overall capacity is not necessarily accomplishing high working capacity under operating conditions, due to insufficient hydrophilicity and/or water stability. Herein, we present a post-synthetic modification (PSM) of MOF-808, with disulfonic acids enhancing simultaneously its hydrophilicity and water stability without sacrificing its uptake capacity of � 30 mmol g À 1 . Di-sulfonic acid PSM enabled a shift of the relative humidity (RH) associated with a sharp step in water vapor sorption from 35-40 % RH in MOF-808 to below 25 % RH. While MOF-808 lost uptake capacity and crystallinity over multiple sorption/desorption cycles, the di-sulfonic acid PSM MOF-808 retained > 80 % of the original capacity. PSM MOF-808 exhibited good hydrothermal stability up to 60 °C and high swing capacity.

Heterogeneity in enzyme/metal–organic framework composites for CO2transformation reactions

“…By adopting the concept of MTV-MOF, there is also a clear opportunity to perform a coordinative PSM using an array of ligands with different functional groups, tailoring the density and diversity of the chemical functionalities on the surface of MOFs, which is underexplored in literature. As an illustration, the introduction of distinct functional groups, including 2-pyridinecarboxyaldehydes, 75 poly(ethylene glycol), 69 and sulfonate, 76 can enable the optimization of the site-specific covalent immobilization, hydrophilicity, and charged properties of the MOF surface, respectively. These modifications can significantly enhance the formation of a stronger and more stable enzyme-MOF interaction, thereby improving the catalytic activity and selectivity.…”

Porous Core‐membrane Microstructured Nanomaterial Composed of Deep Eutectic Solvents and MOF‐808 for CO2 Capture

“…Typically, the chemical reaction could trap more CO 2 molecules into liquid MEA-based DESs, differing from the pure physical change appearing in AcOH-based DESs. In detail, Figure 2d-f and Figure S1 show the normalized 1 H-NMR and 13 C-NMR spectra of four DES samples to further analyze their sorption process and mechanism with the spectral database for organic compounds SDBS, in which the peaks of solvent (deuterated chloroform) are manifested at 7.26 ppm in 1 H-NMR spectra and 77.16 ppm 13 C-NMR spectra. [40] The signals at 2.07 ppm, 11.67 ppm, 20.89 ppm, and 178.21 ppm are related to H in À CH 3 groups and À COOH groups ( 1 H-NMR spectra) as well as C in these groups ( 13 C-NMR spectra), respectively.…”

“…Nevertheless, MOFs generally manifest the disadvantage of weak thermal, chemical, mechanical, and cyclic robustness for CO 2 capture [7–11] . Luckily, MOF‐808 features outstanding thermal stability, excellent mechanical stability, and strong acid tolerance with an octahedral porous framework containing two different types of pores and formate ligands that could be substituted easily [12–15] . Thus, the modification and functionalization of MOF‐808 has been conducted in‐depth exploration to enhance the CO 2 capture performance [16–20] .…”

“…[7][8][9][10][11] Luckily, MOF-808 features outstanding thermal stability, excellent mechanical stability, and strong acid tolerance with an octahedral porous framework containing two different types of pores and formate ligands that could be substituted easily. [12][13][14][15] Thus, the modification and functionalization of MOF-808 has been conducted in-depth exploration to enhance the CO 2 capture performance. [16][17][18][19][20] Park et al introduced several functional groups, including carboxylic acid, amide, and amine, on MOF-808 via a complicated synthesis process with the maximum sorption capacity of approximately 1.62 mmol g À 1 at 298 K and 1 atm, which proved that the reduction of amide into amine significantly enhanced CO 2 capture performance.…”

Drug release and solubility properties of two zeolitic metal–organic frameworks influenced by their hydrophobicity/hydrophilicity

“…Their high drug loading capacity, minimal cytotoxicity, and ease of modification make them an attractive platform for novel drug delivery strategies. [14][15][16][17][18] Over the past few years, the hydrophilicity and hydrophobicity of MOF has emerged as crucial factors influencing water adsorption, [19][20][21] water separation, 22 and self-cleaning. 23 Moreover, the hydrophilicity and hydrophobicity of the MOF porous surface have been at the forefront of research in the development of MOF carriers.…”