Diatomite-Metal-Organic Framework Composite with Hierarchical Pore Structures for Adsorption/Desorption of Hydrogen, Carbon Dioxide and Water Vapor

Abstract

Distinctive Cr-MOF@Da composites have been constructed using chromium-based metal-organic frameworks (MOFs) and diatomite (Da). The new materials have hierarchical pore structures containing micropores, mesopores and macropores. We have synthesized various morphologies of the MOF compound Cr-MIL-101 to combine with Da in a one-pot reaction step. These distinctive hierarchical pore networks within Cr-MIL-101@Da enable exceptional adsorptive performance for a range of molecules, including hydrogen (H2), carbon dioxide (CO2) and water (H2O) vapor. Selectivity for H2 or CO2 can be moderated by the morphology and composition of the Cr-MIL-101 included in the Cr-MOF@Da composite. The encapsulation and growth of Cr-MIL-101 within and on Da have resulted in excellent water retention as well as high thermal and hydrolytic stability. In some cases, Cr-MIL-101@Da composite materials have demonstrated increased thermal stability compared with that of Cr-MIL-101; for example, decomposition temperatures >340 ℃ can be achieved. Furthermore, these Cr-MIL-101@Da composites retain structural and morphological integrity after 60 cycles of repeated hydration/dehydration, and after storage for more than one year. These characteristics are difficult to achieve with many MOF materials, and thus suggest that MOF–mineral composites show high potential for practical gas storage and water vapor capture.

Template-Mediated Synthesis of Hierarchically Porous Metal–Organic Frameworks for Efficient CO2/N2 Separation

“…In addition, grafting basic amine as functional groups in the pore surface via pre-modification with amine-functionalized ligands or post-introduction of amine molecules could also enhance the adsorptivity and selectivity of MOFs through Lewis acid–base interaction between MOFs and CO 2 molecules [ 7 , 9 , 10 ]. However, the success of microporous MOFs under equilibrium conditions in adsorbing pure CO 2 cannot be guaranteed when exposed to the gas mixtures under realistic dynamic conditions because of the high sorption and mass transfer limitations of microporous MOFs [ 9 , 11 , 12 ]. Trade-offs between permeability and selectivity of MOF adsorbents should be carefully considered for realistic dynamic CO 2 separation, which is still a huge change for realistic large-scale separation [ 13 ].…”

UiO-66-NH-(AO) MOFs with a New Ligand BDC-NH-(CN) for Efficient Extraction of Uranium from Seawater

“…4−6 The discovery of MOFs not only breaks through the principal limitation of a relatively small pore size of zeolites and similar oxide-based materials 7 but also broadens the horizon of application in different fields. Recently, MOFs have been used in many applications, such as catalysis, 8,9 adsorption, 10−12 sensing, 13 drug delivery, 14 and gas separation 15,16 because of its high specific surface area, porosity, and adjustability. 17,18 In recent years, MOFs have also been used to extract U from aqueous solutions, 11,12 such as UiO-66-3C4N, 19 MOF-76, 20 HKUST-1, 21 and so on.…”

“…Metal–organic frameworks (MOFs) built by metal ions/ion clusters and organic bridging ligands are classic porous crystalline materials. − The discovery of MOFs not only breaks through the principal limitation of a relatively small pore size of zeolites and similar oxide-based materials but also broadens the horizon of application in different fields. Recently, MOFs have been used in many applications, such as catalysis, , adsorption, − sensing, drug delivery, and gas separation , because of its high specific surface area, porosity, and adjustability. , In recent years, MOFs have also been used to extract U from aqueous solutions, , such as UiO-66-3C4N, MOF-76, HKUST-1, and so on. In addition, the chemical inertness of the original MOF can be changed by introducing special functional groups.…”

A Pressure Swing Approach to Selective CO2 Sequestration Using Functionalized Hypercrosslinked Polymers

“…Over the last two decades, as interest in carbon dioxide capture/utilization (CCS/CCU) has accelerated, numerous sorbents demonstrating CO 2 capturing capabilities have been reported [ 17 , 18 , 19 ], mainly using the temperature swing approach [ 3 , 11 , 12 , 20 ]. These include zeolites [ 21 ], hybrid materials such as metal organic frameworks (MOFs) [ 22 ], activated carbons, ionic liquids [ 23 , 24 ] and microporous organic polymers (MOPs) [ 25 , 26 , 27 , 28 , 29 , 30 , 31 ].…”