An Exceptionally Stable and Water‐Resistant Metal–Organic Framework with Hydrophobic Nanospaces for Extracting Aromatic Pollutants from Water

Abstract

A novel hydrophobic metal-organic framework (MOF), namely Cu2 L (L = 3,3',5,5'-tetraethyl-4,4'-bipyrazolate), is synthesized through a stepwise method, and exhibits an unprecedented 3,4-c net. The exceptionally thermal, chemical, and air stability of this MOF, especially in water and under acidic or basic conditions, and its selective and fast sorption capacity for hydrocarbons over water warrant its direct use for efficient removal of trace organic wastes (e.g. benzene, toluene, xylene, and mixtures thereof) from contaminated water.

A Highly Stable Nonhysteretic {Cu2(tebpz) MOF+water} Molecular Spring

“…Moreover, the thermal (up to 450 °C) and chemical stabilities of Cu 2 (tebpz) exceed those of most MOFs . The chemical stability was tested by suspending the material in boiling solvents (THF, toluene, hexane, DMSO, water) and in acidic (0.001 m HCl) or basic (0.001 m NaOH) aqueous solutions for 24 h. The robustness of the material was attributed not only to the greater basicity and coordination strength of pyrazolate, but also to the hydrophobic channels, which preclude hydrolytic attack …”

“…Cu 2 (tebpz) MOF was synthesized according to the procedure described elsewhere . The as‐synthesized material was subjected to methanol solvent exchange and then thermally activated at 100 °C for 10 h before the water intrusion/extrusion experiments.…”

Application of metal − organic frameworks

“…The MOF Cu 2 L (L ≡ 3,3′,5,5′‐tetraethyl‐4,4′‐bipyrazolate), stable in water both in acidic and basic conditions, can be efficiently employed for the removal of trace organic wastes (i.e. toluene, benzene) from contaminated water . It is worth noting that sometimes a strategy has been used to introduce repellent functional groups in the ligand or in the MOF in order to obstruct water intrusion, enhancing the MOF stability in humid air while maintaining a high sorption capacity toward organic molecules .…”

Explicit treatment of hydrogen bonds in the universal force field: Validation and application for metal-organic frameworks, hydrates, and host-guest complexes

“…[12][13][14] Some MOFs, such as the UiO series, are highly water stable [15], while others break down or transform [16][17][18][19] when exposed to water. Proposed applications of MOFs include separation of organic contaminants [20] and arsenic [21] from aqueous mixtures and capture of water from air [11].…”