Carbon dioxide capture-related gas adsorption and separation in metal-organic frameworks

Metal–organic frameworks have received significant attention as a new class of adsorbents for natural gas storage; however, inconsistencies in reporting high-pressure adsorption data and a lack of comparative studies have made it challenging to evaluate both new and existing materials. Here, we briefly discuss high-pressure adsorption measurements and review efforts to develop metal–organic frameworks with high methane storage capacities. To illustrate the most important properties for evaluating adsorbents for natural gas storage and for designing a next generation of improved materials, six metal–organic frameworks and an activated carbon, with a range of surface areas, pore structures, and surface chemistries representative of the most promising adsorbents for methane storage, are evaluated in detail. High-pressure methane adsorption isotherms are used to compare gravimetric and volumetric capacities, isosteric heats of adsorption, and usable storage capacities. Additionally, the relative importance of increasing volumetric capacity, rather than gravimetric capacity, for extending the driving range of natural gas vehicles is highlighted. Other important systems-level factors, such as thermal management, mechanical properties, and the effects of impurities, are also considered, and potential materials synthesis contributions to improving performance in a complete adsorbed natural gas system are discussed.

https://pubs.rsc.org/en/content/articlepdf/2014/SC/C3SC52633J

Evaluating metal–organic frameworks for natural gas storage

This Review focuses on research oriented toward elucidation of the various aspects that determine adsorption of CO2 in metal–organic frameworks and its separation from gas mixtures found in industrial processes. It includes theoretical, experimental, and combined approaches able to characterize the materials, investigate the adsorption/desorption/reaction properties of the adsorbates inside such environments, screen and design new materials, and analyze additional factors such as material regenerability, stability, effects of impurities, and cost among several factors that influence the effectiveness of the separations. CO2 adsorption, separations, and membranes are reviewed followed by an analysis of the effects of stability, impurities, and process operation conditions on practical applications.

CO2 Capture and Separations Using MOFs: Computational and Experimental Studies

Ionothermal synthesis, the use of ionic liquids as both solvent and template (structure-directing agent), has been used to prepare zeolites and inorganic-organic hybrids such as metal-organic frameworks. The underlying properties of the ionothermal method are discussed, and it is compared with traditional hydrothermal preparative methods. The materials resulting from ionothermal synthesis are described, and any structural features that can be related to the ionic liquid used as the solvent are discussed. Future areas of potential interest are also considered.

Ionothermal synthesis of zeolites, metal-organic frameworks, and inorganic-organic hybrids.

http://digital.csic.es/bitstream/10261/45241/3/Environmental%20impact%20and%20management%20of%20phosphogypsum.pdf

Environmental impact and management of phosphogypsum.

Synthesis and characterization of the one-dimensional zincophosphate Mu-22: [Zn(HPO4)2]8[C5H13N2]8○8 H2O

Synthesis of a new microporous gallophosphate obtained by in situ generation of cyclohexylamine

This work aims to highlight the promising adsorption capacity and kinetic of (poly)chlorobenzene pollutants in the hybrid MIL-101(Cr) type material for technological uses in industrial waste exhaust decontamination. The influence of the MIL-101(Cr) crystal size (nano- and microcrystals) on the adsorption behavior was studied in static and dynamic modes. For this purpose, crystals of MIL-101(Cr) in nano- and micrometric sizes were synthesized and fully characterized. Their sorption properties regarding 1,2-dichlorobenzene were examined using gravimetric method in dynamic (p/p° = 0.5) and static (p/p° = 1) modes at room temperature. 1,2,4-trichlorobenzene adsorption was only performed under static mode because of its too low vapor pressure. 1,2-dichlorobenzene and 1,2,4-trichlorobenzene were used to mimic 2,3-dichlorodibenzo-p-dioxin and 1,2,3,4-tetrachlorodibenzo-p-dioxin, respectively, and more largely dioxin compounds. Adsorptions of these probes were successfully carried out in nano- and microcrystals of MIL-101(Cr). Indeed, in static mode (p/p° = 1) and at room temperature, nanocrystals adsorb 2266 molecules of 1,2-dichlorobenzene and 2093 molecules of 1,2,4-trichlorobenzene per unit cell, whereas microcrystals adsorb 1871 molecules of 1,2-dichlorobenzene and 1631 molecules of 1,2,4-trichlorobenzene per unit cell. In dynamic mode, the 1,2-dichlorobenzene adsorbed amounts are substantially similar to those obtained in static mode. However, the adsorption kinetics are different because of a different scheme of diffusivity of the adsorbate between the two modes. To the best of our knowledge, these adsorption capacities of MIL-101(Cr) as adsorbent for polychlorobenzenes trapping have never been referenced. MIL-101(Cr) appears as a promising material for technological uses in industrial waste exhaust decontamination.

Adsorption of 1,2-dichlorobenzene and 1,2,4-trichlorobenzene in nano- and microsized crystals of MIL-101(Cr): static and dynamic gravimetric studies.

The syntheses and characterization of a series of functionalized MIL-53(In) solids have been reported. Chemical groups with variations in steric hindrance and chemical nature (–(OH)2, –Br or –NO2 groups) were introduced through the terephthalate linker to modify the pore surface. Single crystal X-ray diffraction data, N2 adsorption–desorption isotherms, and infrared spectra were systematically investigated to explore the impact of the functional groups grafted onto the organic linker on the dynamic behaviour of these highly flexible hybrid porous frameworks. Owing to the distinctive steric hindrance and chemical nature, the different substituents can influence the interactions between the framework and the trapped molecules, further influencing the flexibility of the materials. Dihydroxyl modified MIL-53(In) exhibits no nitrogen accessible porosity. Notably, functionalization by –Br and –NO2 groups leads to the different capabilities of the corresponding solids to accommodate N2 molecules.

/pdf/new-functionalized-mil-53-in-solids-syntheses-2zjg3a3zth.pdf

New functionalized MIL-53(In) solids: syntheses, characterization, sorption, and structural flexibility

A two-dimensional microporous fluorogallophosphate, named Mu-35, closely related to ULM-8, was hydrothermally synthesized by in situ generation of the structure-directing agent The precursor of the structure-directing agent is ethylformamide, which is generated in situ by decomposition, and goes on to form ethylamine molecules that act as templates in the medium used for the synthesis The fluorogallophosphate Mu-35 (Mu is Mulhouse), Ga3(PO4)2(HPO4)F3(C2H8N)2(C2H7N)05 (Z = 8), crystallizes in the orthorhombic space group Pbcn with the following unit cell parameters: a = 22117(1), b = 173740(8), c = 101550(4) A The structure of fluorogallophosphate Mu-35 was determined from single-crystal XRD data It exhibits anionic layers composed of an unusual arrangement of three-, five-, and eight-membered rings (MR) [Ga2PO2F, Ga3P2O4F, and Ga3P3O8, respectively], and intercalated by protonated and nonprotonated ethylamine molecules Mu-35 was also characterized by powder XRD, SEM, elemental and thermal analyses, and solid-state NMR spectroscopy (1H, 13C, 19F, and 31P MAS and 1H-31P HETCOR experiments) (© Wiley-VCH Verlag GmbH & Co KGaA, 69451 Weinheim, Germany, 2007)

Angélique Simon-Masseron

Papers

Synthesis and characterization of the one-dimensional zincophosphate Mu-22: [Zn(HPO4)2]8[C5H13N2]8○8 H2O

Synthesis of a new microporous gallophosphate obtained by in situ generation of cyclohexylamine

Adsorption of 1,2-dichlorobenzene and 1,2,4-trichlorobenzene in nano- and microsized crystals of MIL-101(Cr): static and dynamic gravimetric studies.

New functionalized MIL-53(In) solids: syntheses, characterization, sorption, and structural flexibility

Mu‐35: A Fluorogallophosphate Obtained by In Situ Generation of the Template