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Mg(BH4)2 with several polymorphs, known as a high capacity (14.9 wt.%) hydrogen storage material, has become more intriguing due to the recently found new functions of gas physisorption and ionic conductivity. Here we review the state-of-the-art on the energy related functions of Mg(BH4)2. Mg(BH4)2 tends to form the stable intermediate [B12H12]2− when the dehydrogenation temperature is above 400 °C, the strong B-B bonding of which makes the rehydrogenation condition very harsh. In contrast, lower borane intermediate [B3H8]2− facilitates the rehydrogenation even at a mild condition of 100 °C, suggesting the possibility of reversible hydrogen storage in Mg(BH4)2. The porous polymorph γ-Mg(BH4)2 shows attractive gas adsorption properties in view of its unique hydridic surface and pore shape, and potentially can be applied in hydrogen adsorption and Kr/Xe selectivity. A new diffraction-based adsorption methodology was developed to characterize adsorption thermodynamics and kinetics of γ-Mg(BH4)2, providing a novel idea for the characterization of crystalline porous materials. Moreover, the potential of Mg(BH4)2 as an electrolyte is discussed in the last part. Mg(BH4)2·THF/DME acts as a liquid electrolyte in Mg-batteries, while anion substituted or neutral molecule derivatives of Mg(BH4)2 can act as solid-state electrolyte.

Excess adsorption of CO2, CH4, N2, and H2 on ZIF-8 was measured gravimetrically in the pressure range ranging from vacuum to 30 MPa at 298.15, 313.15, 333.15, 353.15, and 394.15 K using a magnetic suspension balance. The textural properties of the adsorbent material─i.e., skeletal density, surface area, pore volume, and pore-size distribution─were estimated by helium gravimetry and N2 (77 K) physisorption. The adsorption isotherms were fitted with the Sips isotherm model and the virial equation, and the values of isosteric heat of adsorption and Henry constants for the gases were determined using the latter.

Enhanced coal bed methane recovery using gas injection can provide increased methane extraction depending on the characteristics of the coal and the gas that is used. Accurate prediction of the extent of gas adsorption by coal are therefore important. Both experimental methods and modeling have been used to assess gas adsorption and its effects, including volumetric and gravimetric techniques, as well as the Ono–Kondo model and other numerical simulations. Thermodynamic parameters may be used to model adsorption on coal surfaces while adsorption isotherms can be used to predict adsorption on coal pores. In addition, density functional theory and grand canonical Monte Carlo methods may be employed. Complementary analytical techniques include Fourier transform infrared, Raman spectroscopy, XR diffraction, and 13C nuclear magnetic resonance spectroscopy. This review summarizes the cutting-edge research concerning the adsorption of CO2, N2, or mixture gas onto coal surfaces and into coal pores based on both experimental studies and simulations.

Advances in materials science and technology have prompted researchers to look to nature for new high-performance, low-cost materials. Among these, cyclodextrins have been widely used as a material in industrial applications. Inspired by previous work by our research group that led to the functionalization of cucurbit[6]uryl and its conversion into supramolecular nanospheres with good CO2 adsorption capacity, this work aims to improve the ability of cyclodextrins to capture CO2 by functionalizing them with amide groups. Carbon dioxide adsorption experiments on functionalized cyclodextrins showed an adsorption capacity similar to that of BEA zeolite, a material currently used in the industry for gas adsorption. Moreover, these adsorption properties could also be exploited to improve the adsorption capacity of drugs, a field in which cyclodextrins are widely used. The new cyclodextrin molecules were characterized by nuclear magnetic resonance spectroscopy and mass spectrometry, thanks to which we could determine the degree of functionalization of the new macrocycles. In addition, using Fourier-transform infrared spectroscopy, we demonstrated the presence and interaction of carbon dioxide adsorbed by the material, whereas an in silico study confirmed the chemisorption as the principal adsorption process, as experimentally inferred using the pseudo-second-order (PSO) kinetic model.

Metal-organic frameworks (MOFs) are among the most promising materials for gas adsorption applications because of their ultrahigh surface areas (up to 8,000 m² g¯¹) and high porosity. Their self-assembly nature of metal ions or clusters and organic ligands allow for high tuneability and a large variety of MOF structures. This creates massive amounts of data relating to MOFs, which together with the computational techniques available, make the computational study of MOFs particularly useful for their rational design. Many computational techniques can be employed and this thesis focuses on two methods: molecular simulations (especially grand canonical Monte Carlo simulations (GCMC)) and machine learning (ML). The objectives of this thesis are therefore to illustrate the applications of these techniques for gas adsorption and how they complement experimental studies, and the use of innovative techniques to advance the study and the rational design of MOFs. An extensive, high-throughput, multi-level computational study of MOFs for natural gas (NG) storage is presented, employing both molecular-level and process-level techniques. The molecular simulations provide insights into the effect of the textural properties in the adsorption process and quantitative structure-property relationships. The best performing MOFs display NG deliverable capacity ~ 450 cm³ g¯¹ (50-7 bar and 298 K), heats of adsorption ~ 5 kJ mol¯¹, and high pore volumes ~ 3 cm³ g¯¹. Process simulations link these microscopic properties with performances in real life. This study identifies the top MOF material for shipping adsorbed natural gas (ANG): a 3D Cu−Cu paddle-wheeled MOF with anthracene-based tetra-carboxylic ligands creating ~ 15 Å hexagonal porous nano-channels with high porosity (pore volume 2.069 cm³ g¯¹ and surface area 5,759 m² g¯¹). This material achieves a high methane deliverable capacity (377 cm³ g¯¹, 151 cm³ cm¯³, and 0.27 g g¯¹). However, the number of possible materials is ever-increasing and might be too large to predict all properties through simulations, therefore, ML is becoming more popular and widely used. Currently, ML methods together with computational techniques are employed to provide a new dimension to the computational study of MOFs. ML algorithms can be used to bypass the need to use more computationally expensive methods such as quantum mechanics and molecular simulations. Partial charges are used to model the adsorbate-MOF electrostatic interaction and are traditionally calculated using quantum mechanics, which is highly accurate but computationally expensive. Calculating highly accurate partial charges is costly and challenging to achieve for a large number of MOFs. A ML method based on a crystal graph is employed to predict partial charges for 8,891 MOFs. It obtains high accuracy (MAE = 0.017 e) for any MOF containing any of the 80 atom types present. The chemical knowledge is fully encoded in the charges and validated with a CO₂ and CO₂-N₂ high-throughput adsorption study (R² > 0.97). This method is finally deployed to 142 MOFs and its transferability is validated for 649 covalent organic frameworks (COFs) (R² = 0.9909). This research allows the automatic prediction of partial charges of new and subsequent MOFs deposited in the CSD MOF subset without the need for quantum mechanics simulations. The model developed in this work equips any scientist with the ability to predict with high accuracy the partial charges of a great variety of existing and future MOFs.

A large number of metal organic frameworks (MOFs) synthesized to date have nodes with a Zn metal, and a detailed understanding of their gas separation efficiency upon metal exchange is needed to pave the way for designing the next generation of MOFs. In this work, we implemented a protocol to identify MOFs with Zn nodes out of 10,221 MOFs and classified them into two main groups. Depending on the pore properties and adsorption selectivities, two MOFs from IRMOFs and two MOFs from ZnO-MOFs were selected. The metal atom (Zn) of the selected four MOFs was exchanged with eight different metals (Cd, Co, Cr, Cu, Mn, Ni, Ti, and V), and 32 different metal-exchanged MOFs (M-MOFs) were obtained. By performing grand canonical Monte Carlo simulations, we investigated the influence of the metal type on the CO2/H-2 and CO2/CH4 separation performances of these 32 M-MOFs. Physical properties of the MOFs such as the pore size and surface area, and chemical properties such as the partial charges of the atoms in the framework were investigated to understand the effect of metal exchange on the gas adsorption and separation performances of materials. Exchange of Zn with V and Cr led to a remarkable increase in the CO2 uptakes of selected MOFs and these increases were reflected on the adsorption selectivity, working capacity, and the adsorbent performance score of MOFs. The exchange of Zn with V increased the selectivity of one of the MOFs from 119 to 355 and the adsorbent performance score from 70 to 444 mol/kg, while for another MOF, exchange of Zn with Cr increased the selectivity from 161 to 921 and the adsorbent performance score from 162 to 1233 mol/kg under the condition of vacuum swing adsorption. The molecular level insights we provided to explain the improvement in the gas separation performances of M-MOFs will serve as a guide to design materials with exceptional CO2 separation performances., European Union (EU); Horizon 2020; European Research Council (ERC); ERC-2017-Starting Grant; Research and Innovation Program; COSMOS

Set of routines to do the advanced alpha-S plot (subtracting pore effect, SPE) analysis for gas adsorption on solids. Full paper (open access) reference: Wang S., Vallejos-Burgos F., Furuse A., Yoshikawa Y., Tanaka H. and Kaneko K. "The subtracting pore effect method for an accurate and reliable surface area determination of porous carbons", Carbon. 175 (2021) 77–86. https://doi.org/10.1016/j.carbon.2020.12.075

Metal–organic frameworks (MOFs), a class of porous nanomaterials, have been widely used in gas adsorption-based applications due to their high porosities and chemical tunability. To facilitate the discovery of high-performance MOFs for different applications, a variety of machine learning models have been developed to predict the gas adsorption capacities of MOFs. Most of the predictive models are developed using traditional machine learning algorithms. However, the continuously increasing sizes of MOF datasets and the complicated relationships between MOFs and their gas adsorption capacities make deep learning a suitable candidate to handle such big data with increased computational power and accuracy. In this study, we developed models for predicting gas adsorption capacities of MOFs using two deep learning algorithms, multilayer perceptron (MLP) and long short-term memory (LSTM) networks, with a hypothetical set of about 130,000 structures of MOFs with methane and carbon dioxide adsorption data at different pressures. The models were evaluated using 10 iterations of 10-fold cross validations and 100 holdout validations. The MLP and LSTM models performed similarly with high prediction accuracy. The models for predicting gas adsorption at a higher pressure outperformed the models for predicting gas adsorption at a lower pressure. The deep learning models are more accurate than the random forest models reported in the literature, especially for predicting gas adsorption capacities at low pressures. Our results demonstrated that deep learning algorithms have a great potential to generate models that can accurately predict the gas adsorption capacities of MOFs.

Coalbed methane (CBM) is an important resource of energy. For CBM recovery, sorption‐induced coal deformation can cause significant reservoir permeability change. Moisture content and coal pore morphology affect the gas adsorption capacity and can alter the coal deformation of the coal seam. Therefore, it is crucial to establish a coal gas moisture‐coupled model for CBM production prediction. However, there are currently insufficient data available for quantitative analyses. In this paper, a series of typical sorption‐induced strain experiments were carried out during methane adsorption and desorption on coal samples with different metamorphic degrees and moisture content. The pore morphology and adsorption capacity of coals were measured to analyze the reason for different deformation of coals with various pore structures and moisture. Results show that the adsorption capacity and deformation is corresponding to the specific surface area of micropore, which first decreases and then increases with coal ranks. The deformation and adsorption gas content of dried coals is greater than that of natural moisture coals, which means that moisture can reduce the sorption capacity of coals, resulting in the decrease of gas adsorption‐induced coal deformation. There is also residual deformation of coal samples after gas desorption caused by the residual adsorbed gas in coals. This paper quantitatively investigates the effects of pore characteristics and moisture on coal deformation and the internal mechanism. This work will provide essential information for building out a fully cross‐coupled model of coal gas‐moisture relationships for CBM production prediction.

Building on the MOF approach to prepare porous materials, herein we report the engineering of porous BN‐doped materials using tricarboxylic hexaarylborazine ligands, which are laterally decorated with functional groups at the full‐carbon ‘inner shell’. Whilst an open porous 3D entangled structure could be obtained from the double interpenetration of two identical metal frameworks derived from the methyl substituted borazine, the chlorine‐functionalised linker undergoes formation of a porous layered 2D honeycomb structure, as shown by single‐crystal X‐ray diffraction analysis. In this architecture, the borazine cores are rotated by 60° in alternating layers, thus generating large rhombohedral channels running perpendicular to the planes of the networks. An analogous unsubstituted full‐carbon metal framework was synthesised for comparison. The resulting MOF revealed a crystalline 3D entangled porous structure, composed by three mutually interpenetrating networks, hence denser than those obtained from the borazine linkers. Their microporosity and CO2 uptake were investigated, with the porous 3D BN‐MOF entangled structure exhibiting a large apparent BET specific surface area (1091 m2 g−1) and significant CO2 reversible adsorption (3.31 mmol g−1) at 1 bar and 273 K., The borazine unit was used to prepare crystalline porous MOFs from specifically designed borazine carboxylate linkers. To evaluate the influence of the borazine rings on the gas adsorption properties, the analogous full‐carbon carboxylate linker and the corresponding MOF were also prepared. The structure of the three MOFs was unambiguously determined by single crystal X‐ray analysis.

Two novel amorphous metal–organic frameworks (aMOFs) with chemical composition {[Zn2(MTA)]·4H2O·3DMF}n (UPJS-13) and {[Cd2(MTA)]·5H2O·4DMF}n (UPJS-14) built from Zn(II) and Cd(II) ions and extended tetrahedral tetraazo-tetracarboxylic acid (H4MTA) as a linker were prepared and characterised. Nitrogen adsorption measurements were performed on as-synthesized (AS), ethanol exchanged (EX) and freeze-dried (FD) materials at different activation temperatures of 60, 80, 100, 120, 150 and 200 °C to obtain the best textural properties. The largest surface areas of 830 m2 g−1 for UPJS-13 (FD) and 1057 m2 g−1 for UPJS-14 (FD) were calculated from the nitrogen adsorption isotherms for freeze-dried materials activated at mild activation temperature (80 °C). Subsequently, the prepared compounds were tested as adsorbents of greenhouse gases, carbon dioxide and methane, measured at high pressures. The maximal adsorption capacities were 30.01 wt% CO2 and 4.84 wt% CH4 for UPJS-13 (FD) and 24.56 wt% CO2 and 6.38 wt% CH4 for UPJS-14 (FD) at 20 bar and 30 °C.

Coal permeability measurements are normally conducted under the assumption that gas pressure in the matrix is equalized with that in fracture and that gas sorption-induced swelling/shrinking strain is uniformly distributed within the coal. However, the validity of this assumption has long been questioned and differential strain between the fracture strain and the bulk strain has long been considered as the primary reason for the inconsistency between experimental data and poroelasticity solutions. Although efforts have been made to incorporate the impact into coal permeability models, the fundamental nature of those efforts to split the matrix strain between fracture and coal bulk remains questionable. In this study, a new concept of differential swelling index (DSI) was derived to theoretically define the relation among sorption-induced strains of the coal bulk, fracture, and coal matrix at the equilibrium state. DSI was a function of the equilibrium pressure and its magnitudes were regulated by the Langmuir constants of both the matrix and the coal bulk. Furthermore, a spectrum of DSI-based coal permeability models was developed to explicitly consider the effect of differential strains. These models were verified with the experimental data under the conditions of uniaxial strain, constant confining pressure, and constant effective stress.

Coal seams, particularly deep unmineable coal reservoirs, are the most important geological desirable formations to store CO2 for mitigating the emissions of greenhouse gas. An advantage of this process is that a huge quantity of CO2 can be sequestrated and stored at relatively low pressure, which will reduce the amount of storage cost required for creating additional platform to store it. The study on CO2 storage in coal seam to enhance coal bed methane (ECBM) recovery has drawn a lot of attention for its worldwide suitability and acceptability and has been conducted since two decades in many coalmines. This article focuses on the coal seam properties related to CO2 adsorption/desorption, coal swelling/shrinkage, diffusion, porosity and permeability changes, thermodynamic/thermochemical process, flue gas injection, etc. Here, the performance analysis of both CO2 storage and ECBM recovery process in coal matrixes is investigated based on the numerical simulation. In this study, a one-dimensional mathematical model of defining mass balances is used to interpret the gas flow and the gas sorption and describe a geomechanical relationship for determining the porosity and the permeability alteration at the time of gas injection. Vital insights are inspected by considering the relevant gas flow dynamics during the displacement and the influences of coal swelling and shrinkage on the ECBM operation. In particular, pure CO2 causes more displacement that is more efficient in terms of total CH4 recovery, whereas the addition of N2 to the mixture assists to make quicker way of the initial methane recovery. However, this study will support future research aspirants working on the same topic by providing a clear conception and limitation about this study.

Covalent organic frameworks (COFs) have emerged as a versatile material platform for such applications as chemical separations, chemical reaction engineering, and energy storage. Their inherently low mechanical stability, however, frequently renders existing methods of pelletization ineffective, contributing to pore collapse, pore blockage, or insufficient densification of crystallites. Here, we present a process for the shaping and densifying of COFs into robust centimeter-scale porous monoliths without the need for templates, additives, or binders. This process minimizes mechanical damage from shear-induced plastic deformation and further provides a network of interparticle mesopores that we exploit in accessing analyte capacities above those achievable from the intrinsic COF structure. Using a lattice-gas model, we accurately capture the monolithic structure across the mesoporous range and tie pore architecture to performance in both gas-storage and -separation applications. Collectively, these results represent a substantial step in the practical applicability of COFs and other mechanically weak porous materials. M.E.C. acknowledges the support of the His Royal Highness the Prince of Wales Commonwealth Scholarship and the Trinity Henry Barlow Scholarship (honorary). N.R. acknowledges the support of the Cambridge International Scholarship and the Trinity Henry Barlow Scholarship (honorary). The X-ray total scattering measurements and multivariate analysis were supported as part of GENESIS: A Next-Generation Synthesis Center, an Energy Frontier Research Center funded by the US Department of Energy (DOE) Office of Science Basic Energy Sciences Program under award number DE-SC0019212. This research used beamline 11-ID-B of the Advanced Photon Source, a US DOE Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under contract no. DE-AC02-06CH11357. D.F.-J. thanks the Royal Society for a university research fellowship. We thank the European Research Council (ERC) under the European Union’s Horizon 2020 Research and Innovation Programme (NanoMOFdeli, ERC-2016-COG 726380) and Innovate UK (104384). J.S.-A. acknowledges financial support from MINECO (PID2019-108453GB-C21). J.-C.T. and M.T. appreciate the ERC Consolidator Grant (PROMOFS 771575) for supporting the research. J.A.M.-I. and F.Z. acknowledge support from the Ministerio de Ciencia e Innovación (PID2019-106268GB-C32).

ACKNOWLEDGMENTS The authors thank SGIker of UPV/EHU and European funding (ERDF and ESF) for technical and human support as well as wish to acknowledge the terrific help of all reviewers of the present manuscript whose comments helped to improve the quality of the work., Supporting Information The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acs.inorgchem.2c00544., Funding E.E. is grateful to the Government of the Basque Country for the predoctoral fellowship and R.F.M. to the Junior Research Position CEECIND/ 00553/2017. The research contract of FF (REF-168-89-ARH/2018) is funded by national funds (OE), through FCT, in the scope of the framework contract foreseen in nos. 4, 5, and 6 of article 23 of the Decree-Law 57/2016, of 29 August, changed by Law 57/2017, of 19 July. This work was developed within the scope of the projects given by the Spanish Ministry of Science, Innovation and Universities (MCIU/AEI/ FEDER, UE) (PGC2018-102052-A-C22, PGC2018-102052-BC21, and PID2019-108028GB-C21), Gobierno Vasco/Eusko Jaurlaritza (IT1310-19 and IT1291-19), Junta de Andalucía (FQM-394), University of the Basque Country (GIU 20/028), and CICECO-Aveiro Institute of Materials (UIDB/50011/ 2020 and UIDP/50011/2020)., Herein, we describe and study a new family of isostructural multifunctional metal–organic frameworks (MOFs) with the formula {[Ln5L6(OH)3(DMF)3]·5H2O}n (where (H2L) is 3-amino-4-hydroxybenzoic acid ligand) for magnetism and photoluminescence. Interestingly, three of the materials (Dy-, Er-, and Yb-based MOFs) present single-molecule magnet (SMM) behavior derived from the magnetic anisotropy of the lanthanide ions as a consequence of the adequate electronic distribution of the coordination environment. Additionally, photoluminescence properties of the ligand in combination with Eu and Tb counterparts were studied, including the heterometallic Eu–Tb mixed MOF that shows potential as ratiometric luminescent thermometers. Finally, the porous nature of the framework allowed showing the CO2 sorption capacity., Government of the Basque Country, Junior Research Position CEECIND/ 00553/2017, National funds (OE), Spanish Ministry of Science, Innovation and Universities (MCIU/AEI/ FEDER, UE) (PGC2018-102052-A-C22, PGC2018-102052-BC21, and PID2019-108028GB-C21), Gobierno Vasco/Eusko Jaurlaritza (IT1310-19 and IT1291-19), Junta de Andalucía (FQM-394), University of the Basque Country (GIU 20/028), CICECO-Aveiro Institute of Materials (UIDB/50011/ 2020 and UIDP/50011/2020)

In recent years, the utilization of three-dimensional (3D) printing has been expanding due to advances in technology and economic efficiency. One of the 3D printing technologies is fused deposition modeling, which can be used to create different kinds of products or prototypes from various polymer filaments. In this study, the activated carbon (AC) coating was introduced to the 3D outputs printed using recycled polymer materials to impart multi-functions such as adsorption of harmful gas and antimicrobial activities. A filament of uniform diameter (1.75 μm) and a filter template in the form of a 3D fabric shape were prepared through the extrusion and 3D printing processes, respectively, of the recycled polymer. In the next process, the 3D filter was developed by coating the nanoporous AC, produced from the pyrolysis fuel oil and waste PET, on the 3D filter template through direct coating. The 3D filters coated with the nanoporous activated carbon showed the enhanced adsorption capacity of 1038.74 mg of SO2 gas and the antibacterial properties of 49% removal of E. coli bacteria. As a model system, a functional gas mask that has harmful gas adsorption abilities and antibacterial properties has been produced by a 3D printing process.

Carbon-dioxide-enhanced shale gas recovery technology has significant potential for large-scale emissions reduction and can help achieve carbon neutrality targets. Previous theoretical studies mainly focused on gas adsorption in one-dimensional pores without considering the influence from the pore geometry. This study evaluates the effects of pore shape on shale gas adsorption. The pure and competitive gas adsorption processes of CO2 and CH4 in nanopores were investigated using molecular simulations to improve the prediction of shale gas recovery efficiency. Meanwhile, quantitative analysis was conducted on the effects of the pore shape on the CO2-EGR efficiency. The results indicate that the density of the adsorption layer in pores is equally distributed in the axial direction when the cone angle is zero; however, when the cone angle is greater than zero, the density of the adsorption layer decreases. Smaller cone-angle pores have stronger gas adsorption affinities, making it challenging to recover the adsorbed CH4 during the pressure drawdown process. Concurrently, this makes the CO2 injection method, based on competitive adsorption, efficient. For pores with larger cone angles, the volume occupied by the free gas is larger; thus, the pressure drawdown method displays relatively high recovery efficiency.

Porous metal–organic framework [Zn2(ttdc)2(bpy)] (1) based on thieno [3,2-b]thiophenedicarboxylate (ttdc) was synthesized and characterized. The structure contains intersected zig-zag channels with an average aperture of 4 × 6 Å and a 49% (v/v) guest-accessible pore volume. Gas adsorption studies confirmed the microporous nature of 1 with a specific surface area (BET model) of 952 m2·g–1 and a pore volume of 0.37 cm3·g–1. Extensive CO2, N2, O2, CO, CH4, C2H2, C2H4 and C2H6 gas adsorption experiments at 273 K and 298 K were carried out, which revealed the great adsorption selectivity of C2H6 over CH4 (IAST selectivity factor 14.8 at 298 K). The sulfur-rich ligands and double framework interpenetration in 1 result in a dense decoration of the inner surface by thiophene heterocyclic moieties, which are known to be effective secondary adsorption sites for carbon dioxide. As a result, remarkable CO2 adsorption selectivities were obtained for CO2/CH4 (11.7) and CO2/N2 (27.2 for CO2:N2 = 1:1, 56.4 for CO2:N2 = 15:85 gas mixtures). The computational DFT calculations revealed the decisive role of the sulfur-containing heterocycle moieties in the adsorption of CO2 and C2H6. High CO2 adsorption selectivity values and a relatively low isosteric heat of CO2 adsorption (31.4 kJ·mol–1) make the porous material 1 a promising candidate for practical separation of biogas as well as for CO2 sequestration from flue gas or natural gas.

The geometrical properties of the reservoir rocks are usually affected by natural thermodynamics or environmental changes that may affect the amount of gas in place in the reservoir. To address these properties, we conduct density functional theory calculations to study the effect of gas composition on the adsorption (Eads), considering surface strain and curvature effects. Additional analyses, like geometrical analysis, and surface energy, were conducted to explain the results. The results of the strain effect showed that regardless of the strain values or curvature levels, all considered gases are physisorbed, with CO2 having the largest Eads. In addition to their weak interaction with the surface, CH4 shows no particular changing trend of the Eads with strain. The effect of strain becomes more pronounced in the case of CO2 and C2H6. A new model of the nanopore, which is the cylindrical-shaped nanopore, is introduced. Cylindrical nanopores have greater adsorption affinity compared to the flat surface, which demonstrates their higher gas capacity. Additionally, a mathematical model of the Eads vs. the diameter is developed. The capacity test of CH4 and CO2 showed adsorption of >24 molecules. These findings can be useful for determining the estimated ultimate recovery in carbonaceous tight gas reservoirs.

The rapid and accurate identification of the physical characteristics of coal by means of ultrasonic detection is of great significance to ensure safe mining of coal and efficient development of coal seam methane. In this paper, the ultrasonic velocity testing experiments of coal during gas adsorption and desorption were carried out, utilizing a low frequency petrophysical measurement device with primary and fractured coal as the research objects. The variations in the elastic mechanical parameters and ultrasonic velocity of coal samples were analyzed to elucidate the influence mechanism that gas adsorption and desorption have on them. During gas adsorption and desorption, the longitudinal wave velocity of the primary structure coal varies from 1990 m/s to 2200 m/s, and the transverse wave velocity varies from 1075 m/s to 1160 m/s, while the longitudinal wave velocity of the fractured structure coal varies from 1540 m/s to 1950 m/s, and the transverse wave velocity varies from 800 m/s to 1000 m/s. The elastic modulus and wave velocities, in both directions of the primary structural coal, were higher than those of the fractured structural coal. In comparison to the fractured structural coal, the main structural coal had a lower Poisson’s ratio. In addition, the spread of the elastic mechanical parameters and wave velocities, in both the longitudinal and transverse directions, was more pronounced in the fracture−structured coal than in the primary−structured coal. During gas adsorption and desorption, the speed of the coal’s longitudinal waves increased, and then decreased, due to the combined effect of gas adsorption expansion and pore gas pressure compression matrix effect. For this experiment, the maximum longitudinal wave velocity of the coal occurred at a gas pressure of 1.5 MPa. Primary structural coal has a longitudinal wave speed of 2103 m/s, whereas fragmented structural coal has a speed of 1925 m/s. The variation in the shear wave velocity of the coal is controlled only by the gas adsorption expansion effects. The shear wave velocity increases during gas adsorption and decreases during gas desorption. With the change of gas pressure, the longitudinal wave velocity can increase by 23.34%, and the shear wave velocity can increase by 17.97%. Coal undergoes changes to both its Poisson’s ratio and elastic modulus as a result of gas adsorption and desorption; these modifications are analogous to the velocity of longitudinal and shear waves, respectively.

Different from the conventional gas reservoirs, gas transport in nanoporous shales is complicated due to multiple transport mechanisms and reservoir characteristics. In this work, we presented a unified apparent gas permeability model for real gas transport in organic and inorganic nanopores, considering real gas effect, organic matter (OM) porosity, Knudsen diffusion, surface diffusion, and stress dependence. Meanwhile, the effects of monolayer and multilayer adsorption on gas transport are included. Then, we validated the model by experimental results. The influences of pore radius, pore pressure, OM porosity, temperature, and stress dependence on gas transport behavior and their contributions to the total apparent gas permeability (AGP) were analyzed. The results show that the adsorption effect causes Kn(OM) > Kn(IM) when the pore pressure is larger than 1 MPa and the pore radius is less than 100 nm. The ratio of the AGP over the intrinsic permeability decreases with an increase in pore radius or pore pressure. For nanopores with a radius of less than 10 nm, the effects of the OM porosity, surface diffusion coefficient, and temperature on gas transport cannot be negligible. Moreover, the surface diffusion almost dominates in nanopores with a radius less than 2 nm under high OM porosity conditions. For the small-radius and low-pressure conditions, gas transport is governed by the Knudsen diffusion in nanopores. This study focuses on revealing gas transport behavior in nanoporous shales.

Coal deformation caused by gas adsorption is a well‐known phenomenon and has played an important role in many engineering fields. For example, the bulk coal deformation induced by gas is a primary factor in coal and gas outbursts, and the changes in coalbed permeability are primarily determined by the evolution of the coal fracture volumetric strain during gas recovery. However, the current models of coal deformation induced by gas do not fully consider the coal seam field conditions or the deformation factors. To better fit coal seam field conditions and provide a basis for engineering applications, in this work, based on coal's physical structure, coal seam field conditions, the energy balance approach, poroelasticity, mathematical differentiation, and previous scholars' research results, the volumetric strain models of bulk coal, coal fracture, and coal matrix under coal seam field conditions are established. In addition, based on the analysis of the effect of gas pressure on coal deformation, the difference in gas pressure effects on the bulk coal deformation between experimental conditions and coal seam field conditions revealed that when the bulk coal deformation is tested in a laboratory, the gas pressure exerts a compressive effect on the bulk coal. However, under coal seam field conditions, the gas pressure has a swelling effect on the bulk coal. Additionally, gas pressure exerts an compression on the coal matrix and a swelling on the coal fracture under coal seam field conditions. At the end of the paper, the established models were analyzed and discussed from multiple perspectives. It was shown that the coal deformation models established in this paper are all accurate and reliable.

CERVOXY COLL; International audience; A growing interest is currently directed to find an efficient NO and CO2 gas carriers for biomedical applications. The gas adsorption properties of sodium- (Na-X) and copper- (Cu-X) containing FAU nanozeolites toward nitric oxide and carbon dioxide were studied. The materials were fully characterised by XRD, TEM, ICP, DLS and in-situ FTIR. The as-prepared Na-X showed higher gas adsorption ability towards carbon dioxide, whereas the ion-exchanged Cu-X was more efficient adsorbent with regards to nitric oxide. In addition, the cytotoxicity tests disclosed that both nanozeolites have no toxicity making them suitable for further tests in biomedical field as gas transporters.

Understanding the nature of pore structures in unconventional reservoirs such as shale oil/gas can assist in evaluating the storage potentials and reveal transport mechanisms. Pore size distribution is one of the most importance pore structure parameters which needs to be evaluated accurately and presented in various formats to provide more in-depth information from the rocks. In this paper, several shale samples were collected and analyzed by using N 2 adsorption and high-pressure mercury intrusion. Three different presentations of the pore size distributions: incremental pore volume versus diameter ( DV ), differential pore volume versus diameter ( DV/Dd ) and the log differential pore volume versus diameter ( DV/DlogD ) were calculated from these two different methods, respectively. The comparison results showed that different presentations from the same sample could demonstrate various type of important pore information. The DV curve is largely depended on the experimental data spacing while the other two presentations do not. The DV/Dd curve could amplify the role of smaller pore ranges while the DV/Dlogd would represent the importance of the larger pore ranges. The multifractal analysis showed that the heterogeneity index calculated from the DV/Dd curve is much larger than the heterogeneity index from the DV/Dlog curve. It was concluded that DV/Dd is more suitable for characterizing the pore size distribution from N 2 adsorption while DV/Dlogd works better for the high-pressure mercury intrusion. Cited as : Liu, K., Ostadhassan, M. The impact of pore size distribution data presentation format on pore structure interpretation of shales. Advances in Geo-Energy Research, 2019, 3(2): 187-197, doi: 10.26804/ager.2019.02.08

Cationic frameworks are an emerging class of exceptional solid adsorbents capable of encapsulating highly toxic and persistent anionic pollutants. The controlled generation of cationic frameworks, however, lags behind the abundant design strategies devised to control the structures and topologies of neutral frameworks. In this regard, we report a rational approach that allows the conversion of the synthetic approach toward constructing a neutral framework into one allowing for the synthesis of a cationic one without incurring any changes to the overall topology or the selected metal ion. We demonstrate that the replacement of a functional group on an organic linker that promotes a similar coordination mode, but bearing one less negative charge, can yield the systematic generation of cationic frameworks. Moreover, we confirm the cationic nature of the metal-organic frameworks through preliminary anion-exchange experiments and propose a method to retain permanent porosity in cationic frameworks through the use of strongly binding anions. Altogether, these results show great promise for the construction of tunable nanoporous frameworks capable of carrying out anion-exchange processes.

Metal-organic frameworks (MOFs) are a new class of microporous materials that possess framework flexibility, large surface areas, “tailor-made” framework functionalities, and tunable pore sizes. These features empower MOFs superior performances and broader application spectra than those of zeolites and phosphine-based molecular sieves. In parallel with designing new structures and new chemistry of MOFs, the observation of unique breathing behaviors upon adsorption of gases or solvents stimulates their potential applications as host materials in gas storage for renewable energy. This has attracted intense research energy to understand the causes at the atomic level, using in situ X-ray diffraction, calorimetry, Fourier transform infrared spectroscopy, and molecular dynamics simulations. This article is developed in the following order: first to introduce the definition of MOFs and the observation of their framework flexibility. Second, synthesis routes of MOFs are summarized with the emphasis on the hydrothermal synthesis, owing to the environmental-benign and economically availability of water. Third, MOFs exhibiting breathing behaviors are summarized, followed by rationales from thermodynamic viewpoint. Subsequently, effects of various functionalities on breathing behaviors are appraised, including using post-synthetic modification routes. Finally, possible framework spatial requirements of MOFs for yielding breathing behaviors are highlighted as the design strategies for new syntheses.

Here we report the subcomponent self‐assembly of a truxene‐faced Zn4L4 tetrahedron, which is capable of binding the smallest hydrocarbons in solution. By deliberately incorporating inward‐facing ethyl groups on the truxene faces, the resulting partially‐filled cage cavity was tailored to encapsulate methane, ethane, and ethene via van der Waals interactions at atmospheric pressure in acetonitrile, and also in the amorphous solid state. Interestingly, gas capture showed divergent selectivities in solution and the amorphous solid state. The selective binding may prove useful in designing new processes for the purification of methane and ethane as feedstocks for chemical synthesis., A Zn4L4 coordination cage enabled entrapment of gases in both solution and the amorphous solid state at atmospheric pressure. The lipophilic cavity of the cage was designed through a cavity‐filling strategy, which could bind small hydrocarbon gases. A contrasting selectivity of gas capture was observed in solution and the solid state, showing the potential of the cage to be engineered as porous liquids or solid adsorbents for gas separation.

The development of nanostructured composites made of metal-organic frameworks (MOFs) and graphene-based components, including exfoliated nanoplates of graphene oxide (GO) or reduced (rGO) graphene oxide, is an area of great interest in gas storage and separation. To improve the industrial viability, it is commonly demanded to build these nanocomposites with the shape of compact units, such as monoliths, foams, pellets, or films. Methods to generate those 3D nanocomposites involving rGO are abundant; however, they become scarce when GO is the desired support due to the difficulty in maintaining the carbon matrix oxidized during the structuration process. In this work, a methodology based on the use of supercritical CO2 (scCO2) is described for the synthesis of nanocomposites involving a discontinuous MOF phase, e.g. nanoparticles (NPs) of HKUST-1, decorating the surface of a continuous GO matrix, with surface oxygen groups favoring MOF attachment. The use of this new supercritical methodology allows the nanostructuration of the composite in the form of 3D aerogels while avoiding the reduction of GO. Enhanced values of textural properties, determined by low-temperature N2 adsorption-desorption, were observed for the nanocomposites in comparison to the values calculated for similar physical mixtures, highlighting an increase of 40-45% in the value of the surface area for samples with a high percentage of HKUST-1. Moreover, the composite aerogels, displaying a type II isotherm, outperform pristine HKUST-1 in regard to the CH4 practical working capacity at high pressure. Particularly, a composite exhibiting more than 2-fold the working capacity of net HKUST-1 NPs was obtained. Columns involving the composite aerogel as the stationary phase were used to study the separation of N2/CO2 and CH4/CO2 gas mixtures. The results showed a high selectivity of the nanostructured HKUST-1@GO composites for CO2, with breakthrough times of ca. 20 min g-1 and stable cyclic operations., This work was supported by the Spanish Ministry of Science and Innovation MICINN through the Severo Ochoa Program for Centers of Excellence (SEV-2015-0496 and CEX2019-000917-S) and the Spanish National Plan of Research with projects CTQ2017-83632, PID2020-115631GB-I00, CTQ2016-75150-R, CTQ2017-84692-R, RTI2018-100832-B-I00, and PID2019-106832RB-I00. J.A.R.N. thanks Junta de Andalucia (P18-RT-612). K.C.S. thanks the Department of Chemistry through start-up funding. This work has been done in the framework of the doctoral program “Chemistry” of the Universitat Autònoma de Barcelona by A.R., A.B., and J.F.; A.R. and A.B. acknowledge FPI grants.

IF/01016/2014 SFRH/BD/139627/2018 PTDC/CTMCTM/30326/2017 PTDC/EQU-EQU/32050/2017 PTDC/FIS-MAC/28157/2017 UIDB/50006/2020 UIDP/50006/2020 Global warming is arguably the biggest scientific challenge of the twenty-first century and its environmental consequences are already noticeable. To mitigate the emissions of greenhouse gases, particularly of CO2, there is an urgent need to design materials with improved adsorbent properties. Five different magnetic ionic liquids were impregnated into the metal–organic framework ZIF-8. The composites were produced by a direct-contact method, and their performance as sorbents for gas separation applications was studied. The impact of the ionic liquid anion on the sorption capacity and ideal CO2/CH4 and CO2/N2 selectivities were studied, focusing on understanding the influence of metal atom and ligand on the adsorbent properties. Reproducible methodology, along with rigorous characterization, were established to assess the impact of the ionic liquid on the performance of the composite materials. Results show that the ionic liquid was well-impregnated, and the ZIF-8 structure was maintained after ionic liquid impregnation. The produced composites were of microporous nature and were thermally stable. CO2, CH4, and N2 adsorption–desorption isotherms were obtained at 303 K and between 0 and 16 bar. The adsorption-desorption data of the composites were compared with that obtained for original ZIF-8. The general trend in composites is that the increased gas uptake per available pore volume compensates the pore volume loss. Adsorption data per unit mass showed that composites have reversible sorption, but inferior gas uptake at all pressure ranges. This is due to the observed total pore volume loss by the ionic liquid pore occupation/blockage. In most cases, composites showed superior selectivity performance at all pressure range. In particular, the composite [C4MIM]2[MnCl4]@ZIF-8 shows a different low-pressure selectivity trend from the original MOF, with a 33% increase in the CO2/N2 selectivity at 1 bar and 19% increase in the CO2/CH4 selectivity at 10 bar. This material shows potential for use in a post-combustion CO2 capture application that can contribute to greenhouse gas mitigation. publishersversion published

Global warming is arguably the biggest scientific challenge of the twenty-first century and its environmental consequences are already noticeable. To mitigate the emissions of greenhouse gases, particularly of CO2, there is an urgent need to design materials with improved adsorbent properties. Five different magnetic ionic liquids were impregnated into the metal–organic framework ZIF-8. The composites were produced by a direct-contact method, and their performance as sorbents for gas separation applications was studied. The impact of the ionic liquid anion on the sorption capacity and ideal CO2/CH4 and CO2/N2 selectivities were studied, focusing on understanding the influence of metal atom and ligand on the adsorbent properties. Reproducible methodology, along with rigorous characterization, were established to assess the impact of the ionic liquid on the performance of the composite materials. Results show that the ionic liquid was well-impregnated, and the ZIF-8 structure was maintained after ionic liquid impregnation. The produced composites were of microporous nature and were thermally stable. CO2, CH4, and N2 adsorption–desorption isotherms were obtained at 303 K and between 0 and 16 bar. The adsorption-desorption data of the composites were compared with that obtained for original ZIF-8. The general trend in composites is that the increased gas uptake per available pore volume compensates the pore volume loss. Adsorption data per unit mass showed that composites have reversible sorption, but inferior gas uptake at all pressure ranges. This is due to the observed total pore volume loss by the ionic liquid pore occupation/blockage. In most cases, composites showed superior selectivity performance at all pressure range. In particular, the composite [C4MIM]2[MnCl4]@ZIF-8 shows a different low-pressure selectivity trend from the original MOF, with a 33% increase in the CO2/N2 selectivity at 1 bar and 19% increase in the CO2/CH4 selectivity at 10 bar. This material shows potential for use in a post-combustion CO2 capture application that can contribute to greenhouse gas mitigation.

We investigate the effect of pressure and gas species on the electrical transport in nanosheets of palladium diselenide (PdSe2) and molybdenum disulfide (MOS2), used as the channel of back-gate field-effect transistors. Air pressure can control the carrier polarity in PdSe2 devices and the dominant n-type conduction in a high vacuum can reversibly transform in p-type transport at atmospheric pressure. Structural defects facilitate gas adsorption, which widens the hysteresis of the transfer characteristics. For Mos2 the hysteresis has a monotonic dependence on gas adsorption energy. We investigate the effect of low-energy electron irradiation and find that few tens e−/nm2 fluence can significantly change the transistor characteristics. Finally, the field emission currents from both PdSe2 and Mos2 nanoflakes are measured. The first experimental observation of the gate modulation of the field emission current from a Mos2 monolayer is reported. Such a finding constitutes the proof-of-concept of a field-effect transistor based on field emission and paves the way for new applications of 2D materials in vacuum electronics.

In this Minireview, we discuss the fundamental chemistry of soft porous crystals (SPCs) by characterizing their common structural features and the resulting structural softness and transitions. In particular, we focus on the recently emerging properties based on metastable transitions and those arising from local dynamics. By comparing the resulting adsorption properties to those of commonly applied rigid adsorbents, we highlight the potential of SPCs to revolutionize adsorption-based technologies, considering our current understanding of the thermodynamic and kinetic aspects. We provide brief outlines for the experimental and computational characterization of such phenomena and offer an outlook toward next-generation SPCs likely to be discovered in the next decade.

Conjugated microporous polymers (CMPs) have conjugated skeleton and permanent porosity, and exhibit huge potential in developing novel functional materials for resolving the challenging energy and environment issues. Metal-containing CMPs often exhibited unique properties. In the present manuscript, ferrocene-based conjugated microporous polymers (FcCMPs) were designed and synthesized with 1,1'-dibromoferrocene and 5,10,15,20-Tetrakis(4- bromophenyl) porphyrin (FcCMP-1) or Tetra (p-bromophenyl) methane (FcCMP-2) as building units via Yamamoto coupling. FcCMPs were amorphous, and exhibited excellent thermal and physicochemical&nbsp, stability.&nbsp, The BET surface area of FcCMP-1 and FcCMP-2 was 638 m2/g and 422 m2/g, respectively. In comparison with FcCMP-2, FcCMP-1 displayed better gas storage capacity due to higher porosity. FcCMPs were also used as an adsorbent for removal of methyl violet from aqueous solution, and exhibited excellent adsorption properties due to the interaction between electron-rich conjugated structure of the polymers and methyl violet with cationic groups. Moreover, FcCMPs could be extracted and regenerated by an eluent and then re-used for high efficient removal of methyl violet.

In this study, we combined experiments with high-throughput molecular simulation methods to unlock CO2/N2 separation performances of 1085 different types of ionic liquid (IL)/metal organic framework (MOF) composites. We first validated the accuracy of our proposed computational methodology by synthesizing and characterizing three different IL/MOF composites composed of [BMIM][BF4] (1-n-butyl-3-methylimidazolium tetrafluoroborate) and by comparing their experimental CO2, N2 adsorption and separation performances with the simulation results. Motivated from the good agreement between experiments and simulations, we performed a high-throughput computational screening of 1085 different types of MOFs and their [BMIM][BF4]-incorporated counterparts to compute adsorption of CO2/N2 mixture in each material. Adsorbent performance evaluation metrics of [BMIM][BF4]/MOF composites including selectivity, working capacity, adsorbent performance score, and regenerability were calculated and compared with those of pristine MOFs to assess adsorption-based CO2/N2 separation performance limits of the composite materials. Our results revealed that [BMIM][BF4] incorporation remarkably increases CO2 selectivity, CO2 working capacity, and adsorption performance score of very large numbers of MOFs, resulting in excellent adsorbent candidates for separation of flue gas mixture. Analysis of the structure-performance relations showed that composites having narrow pore sizes, low porosities, and high IL loadings offer high CO2/N2 selectivities. These results will be useful in guiding and accelerating the design and development of new IL/MOF composites having exceptional CO2 capture performances from flue gas mixtures., European Research Council (ERC); European Union (European Union); Horizon 2020; Research and Innovation Programme; ERC-2017-Starting Grant; Scientific and Technological Research Council of Turkey (TÜBİTAK), 1001 Scientific and Technological Research Projects Funding Program; Koҫ University Seed Fund Program

Three microporous organic frameworks (hereafter denoted as MPOF-Ads) based on a rigid adamantane core have been successfully synthesized via Sonogashira-Hagihara polycondensation coupling in high yields, 83.7-94.6%. The obtained amorphous MPOF-Ads networks have high Brunauer-Emmett-Teller surface areas (up to 737.3 m g), narrow pore size distribution (0.95-1.06 nm), and superior thermal (the initial decomposition temperature T under an N atmosphere can reach 410 °C) and chemical stability (no apparent degradation in common organic solvents or strong acid/base solutions after 7 days). At 273 K and 1.0 bar, these MPOF-Ads networks present good uptake capacities for small gas molecules (13.9 wt % CO and 1.66 wt % CH) for which the presence of high surface area, predominant microporosity, and narrow pore size distribution are beneficial. In addition, the as-prepared MPOF-Ads networks possess moderate isosteric heats for CO (Q = 19.5-30.3 kJ mol) and show desired CO/N and CO/CH selectivity (36.3-38.4 and 4.1-4.3 based on Henry's law and 17.88-24.92 and 4.24-5.70 based on ideal adsorbed solution theory, respectively). With the demonstrated properties, the synthesized MPOF-Ads networks display potential for small gas storage and separation that can be used in harsh environments because of their superior physical and chemical stability., This work was supported by the National Natural Science Foundation of China (nos. 21476051, 21706039), Natural Science Foundation of Guangdong Province (no. 2017A030310300), Science and Technology Program of Guangzhou City (no. 201704030075), and Innovation Team Project in Universities of Guangdong province (no. 2017GKCXTD006). P.S.S. acknowledges the Spanish Ministry of Economy and Competitivity (MINECO) for a Ramón y Cajal fellowship (RYC-2014-16759) and the Proyecto de Investigación en el Programa Estatal de Fomento de la Investigacioń Cientifí ca y Teć nica de Excelencia (MAT2017- 88382-P). The authors are grateful to Wenzhao Jiang for her help with the sample (MPOF-Ads) synthesis experiments. We also thank Dr. Z. Lin for his kind suggestions on the “Introduction”

Superabsorbent hydrogels are three-dimensional macromolecular compounds that can absorb and retain large amounts of water. One benefit of amending soils with hydrogels includes better soil structure (i.e., pore network), which can lead to an increase in the retention of water and nutrients, and thus improve crop yield. The objectives of this study were to 1) evaluate the effect of superabsorbent hydrogels on the specific porosity and pore size distribution of three soils and 2) estimate soil swelling from HG application. Two hydrogels (polyacrylate “CI” and cellulose-based “H30”) were used in a randomized complete block design with three soil types (sand (S), sandy loam (SL), and clay (C)), three treatments (CI, H30, and CTRL (control)), with three replicates each. Specific porosity and pore size distribution were measured with three techniques (gas adsorption, mercury intrusion porosimetry, and x-ray computed microtomography) measuring a pore diameter range from 0.4 nm to 2163 µm. Our results showed that while not always significant, HG amended soils had an overall increased porosity >12% regarding macroporosity (i.e., pores >828 µm) compared to the CTRL treatment. Both HGs caused soil volume change from −37% (shrinkage) to 6% (swelling); however, H30 caused significantly lower rates compared to CI, possibly due to soil-like substances incorporated into the H30 structure. Because of this, further studies investigating the interaction between different moisture contents and H30 should be conducted to determine if H30 helps to maintain soil structure.

Takeru Omiya, Koki Sasaki, Yoshiaki Uchida et al. Nanosheet Synthesis of Metal Organic Frameworks in a Sandwich-like Reaction Field for Enhanced Gate-Opening Pressures. ACS Applied Nano Materials, 1 (8), 3779-3784, August 18, © 2018 American Chemical Society. https://doi.org/10.1021/acsanm.8b01151, Elastic layer-structured metal-organic frameworks (ELMs) are a family of flexible nanoporous metal organic frameworks (MOFs) showing gate-opening gas adsorption. The gate-opening pressure shifts to a higher value by crystal downsizing. However, the MOF nanoparticles and nanorods showing the gate-opening gas adsorption grow more than 50 nm even for their shortest sides. Here, we describe the synthesis and unique gas adsorption behavior of the first example of nanosheets of ELMs (ELM-NSs). The thickness and horizontal width of the ELM-NSs obtained from a new synthetic method using the inside the bilayers in hyperswollen lyotropic lamellar (HL) phases as sandwich-like reaction fields (SRFs) are a few nanometers and several hundreds of nanometers, respectively. The previously reported rationalization of the temperature dependence of the gate-opening pressures for ELMs enables us to discuss the size effects in terms of the adsorption-induced structural transitions and the Helmholtz free energy change of the host.

Ruthenium-containing organometallic ionic liquids with the B(CN)(4) anion were developed that generate microporous amorphous coordination polymers upon UV irradiation. UV light irradiation of [Ru(C5H5)(C6H5R)][B(CN)(4)] (R = butyl, ethyl, octyl) quantitatively generated a yellow powder of a coordination polymer with the formula [Ru(C5H5){B(CN)(4)}](n). In this reaction, the arene ligand is eliminated by UV irradiation and coordination polymer is formed by coordination of the cyano groups of the anion to the Ru ion. The photogenerated solids exhibited nitrogen absorption properties due to their microporous structure. This paper proposes a method to fabricate functional coordination polymers by photoirradiation of liquids.

Herein, we have used density functional theory (DFT) to investigate the adsorption behavior of gas molecules on Co/N3 co–doped graphene (Co/N3–gra). We have investigated the geometric stability, electric properties, and magnetic properties comprehensively upon the interaction between Co/N3–gra and gas molecules. The binding energy of Co is −5.13 eV, which is big enough for application in gas adsorption. For the adsorption of C2H4, CO, NO2, and SO2 on Co/N–gra, the molecules may act as donors or acceptors of electrons, which can lead to charge transfer (range from 0.38 to 0.7 e) and eventually change the conductivity of Co/N–gra. The CO adsorbed Co/N3–gra complex exhibits a semiconductor property and the NO2/SO2 adsorption can regulate the magnetic properties of Co/N3–gra. Moreover, the Co/N3–gra system can be applied as a gas sensor of CO and SO2 with high stability. Thus, we assume that our results can pave the way for the further study of gas sensor and spintronic devices.

A low energy ion source based on carbon nanotube (CNT) electron emitter was constructed for calibrating the ion-mode of mass spectrometer or other ion detectors. The field emission properties of CNT for CH4 were tested in the experiments. The field emission current increases along with the pressure rise of CH4 from 10−6 Pa to 10−4 Pa in a short time, but the degradation of field emission current was found in nearly 2 hours storage in CH4 with pressure of 10−4 Pa. While the CH4 was introduced as the operation gas in ion source, the maximum CH4+ ion current of 45 pA, and the sensitivity of 1.76 Pa−1 with the relative standard deviation (RSD) 4.9% could be obtained.

A highly water and thermally stable metal-organic framework (MOF) Zn2(Pydc)(Ata)2 (1, H2Pydc = 3,5-pyridinedicarboxylic acid; HAta = 3-amino-1,2,4-triazole) was synthesized on a large scale using inexpensive commercially available ligands for efficient separation of C2H2 from CH4 and CO2. Compound 1 could take up 47.2 mL/g of C2H2 under ambient conditions but only 33.0 mL/g of CO2 and 19.1 mL/g of CH4. The calculated ideal absorbed solution theory (IAST) selectivities for equimolar C2H2/CO2 and C2H2/CH4 were 5.1 and 21.5, respectively, comparable to those many popular MOFs. The Qst values for C2H2, CO2, and CH4 at a near-zero loading in 1 were 43.1, 32.1, and 22.5 kJ mol−1, respectively. The practical separation performance for C2H2/CO2 mixtures was further confirmed by column breakthrough experiments.

International audience; Graphene, when doped with transition metals, is considered, both experimentally and theoretically, as a good candidate for the detection of gas molecules as CO, CO2, NO or NO2. This opens new perspectives for gas sensor set-ups considering that devices based on 2 dimensional graphene are more sensitive to detect molecules than solid-state gas sensors. The state of the arts on gas adsorption on Fe doped armchair graphene nanoribbons (Fe-AGNR) is still in its starting phase and thorough investigations of the mechanism of the adsorption on graphene need to be done. In the present work, the electronic and transport properties of molecules adsorbed on Fe-AGNR are scrutinized using ab-initio calculations. We observe that the adsorption of gas molecules on Fe-AGNR changes significantly the electronic properties of both the valence and the conduction band. Besides, The adsorbed molecules change the local electron density of states of the graphene nanoribbons, modifying thus the conductivity, being one of the main output quantity of the gas sensors. We also observe that the adsorbed molecules induce specific impurity bands which play a role in the transport properties. Finally, considering the observed variations of electrical conductance induced by the molecules, we propose several strategies to set-up gas sensors for CO, CO2, NO and NO2 molecules. These strategies are either based on the measurement of the conductance in the valence or the conduction band (using either p or n-doped Fe-AGNR) or to the spin polarization induced by the NO and NO2 molecules.

The paper presents results of conducting research on the development of a certified reference material (CRM) for specific surface area of quartz sand, which is practically non-porous and therefore has low specific surface area value ~ 0.8 m 2 /g. The standard uncertainty due to RM inhomogeneity, the standard uncertainty due to RM instability, as well as the standard uncertainty due to characterization were estimated using the State Primary Standard GET 210‑2014 for Units of Specific Absorption of Gases, Specific Surface Area, Specific Volume, and Pore Size of Solid Substances and Materials. The metrological characteristics of the CRM were determined using a low-temperature gas adsorption method. Krypton was used as an adsorbate to increase measurement accuracy.

A nanoporous metal–organic framework material, exhibiting an IRMOF-1 type crystalline structure, was prepared by following a direct solvothermal synthesis approach, using zinc nitrate and terephthalic acid as precursors and dimethylformamide as solvent, combined with supercritical CO2 activation and vacuum outgassing procedures. A series of advanced characterization methods were employed, including scanning electron microscopy, Fourier-transform infrared radiation spectroscopy and X-ray diffraction, in order to study the morphology, surface chemistry and structure of the IRMOF-1 material directly upon its synthesis. Porosity properties, such as Brunauer–Emmet–Teller (BET) specific area (∼520 m2/g) and micropore volume (∼0.2 cm3/g), were calculated for the activated sample based on N2 gas sorption data collected at 77 K. The H2 storage performance was preliminary assessed by low-pressure (0–1 bar) H2 gas adsorption and desorption measurements at 77 K. The activated IRMOF-1 material of this study demonstrated a fully reversible H2 sorption behavior combined with an adequate gravimetric H2 uptake relative to its BET specific area, thus achieving a value of ∼1 wt.% under close-to-atmospheric pressure conditions. © 2017 Hydrogen Energy Publications LLC 42 23899 23907 23899-23907

Mineral surfaces play a critical role in the solar nebula as a catalytic surface for chemical reactions and potentially acted as a source of water during Earth's accretion by the adsorption of water molecules to the surface of interplanetary dust particles. However, nothing is known about how mineral surfaces respond to short-lived thermal fluctuations that are below the melting temperature of the mineral. Here we show that mineral surfaces react and rearrange within minutes to changes in their local environment despite being far below their melting temperature. Polished surfaces of the rock and planetary dust-forming silicate mineral olivine ((Mg,Fe)2SiO4) show significant surface reorganization textures upon rapid heating resulting in surface features up to 40 nm in height observed after annealing at 1200 °C. Thus, high-temperature fluctuations should provide new and highly reactive sites for chemical reactions on nebula mineral particles. Our results also may help to explain discrepancies between short and long diffusion profiles in experiments where diffusion length scales are of the order of 100 nm or less.

The gas–liquid membrane contactor forms a gas–solid–liquid interface and has a high potential for the applications in gas adsorption, catalysis, energy exchange, and so on. Porous superhydrophobic membranes show a great gas separation/adsorption ability. However, the complicated device architecture and the durability issue are normally concerned especially for the continuous circulation of gas and liquid. In this work, we present a free-standing gas-conductive circuit simply formed by connecting the superamphiphobic porous monoliths (SAPMs) to achieve an efficient under-liquid gas adsorption. The porous worm-like SAPM is prepared with low-temperature expandable graphite and polyvinylidenefluoride, exhibiting superamphiphobicity and superaerophilicity after fluoridation. The as-made SAPM circuits can be used as a reliable gas conductor under numerous liquids, such as water, alkaline, acidic, and oily solutions. In this work, the CO2 adsorption capacities of the SAPM circuits are evaluated under NaOH and methyldiethanolamine solutions and the mass transfer rate can reach up to 9.61 mmol m–2 s–1. Moreover, the effective human blood oxygenation process is also demonstrated using SAPM circuits. Thus, the reported SAPM provides an alternative gas–liquid exchanging method and the simplified process could be of great benefit to the cost-effectively large-scale CO2 capture or gas exchanging applications.

Three stereoisomers of Troger’s Base-based dimeric macrocycles Trogerophane 1 (T1) including one pair of enantiomers (rac-T1) and one meso isomer (R2NS2N-T1) were obtained and fully characterized by X-ray analysis. In the crystalline stacking state R2NS2N-T1 showed heterochiral self-sorting behavior along a axis with cofacial π-π stacking interactions, while rac-T1 showed heterochiral self-sorting behavior along c axis with slipped π-π stacking interactions, respectively. Meanwhile both of them showed homochiral self-sorting behavior along b axis as well as one pair of supramolecular helixes were formed in both cases. All the self-sorting behaviors are controlled by two chiral Troger’s Base units from neighbouring molecules. To the best of our knowledge, such chiral self-sorting and supramolecular helixes of N-centered chiral superstructures is a rare example. In addition, R2NS2N-T1 and rac-T1 demonstrated different adsorption capacities towards the vapor of dichloromethane and acetone, respectively.

Herein, a hybrid Monte Carlo (MC)/molecular dynamics (MD) simulation protocol that properly accounts for the extraordinary structural flexibility of metal-organic frameworks (MOFs) is developed and validated. This is vital to accurately predict gas adsorption isotherms and guest-induced flexibility of these materials. First, the performance of three recent models to predict adsorption isotherms and flexibility in MOFs is critically investigated. While these methods succeed in providing qualitative insight in the gas adsorption process in MOFs, their accuracy remains limited as the intrinsic flexibility of these materials is very hard to account for. To overcome this challenge, a hybrid MC/MD simulation protocol that is specifically designed to handle the flexibility of the adsorbent, including the shape flexibility, is introduced, thereby unifying the strengths of the previous models. It is demonstrated that the application of this new protocol to the adsorption of neon, argon, xenon, methane, and carbon dioxide in MIL-53(Al), a prototypical flexible MOF, substantially decreases the inaccuracy of the obtained adsorption isotherms and predicted guest-induced flexibility. As a result, this method is ideally suited to rationalize the adsorption performance of flexible nanoporous materials at the molecular level, paving the way for the conscious design of MOFs as industrial adsorbents.

The analysis of porosity and pore structure of shale rocks has received special attention in the last decades as unconventional reservoir hydrocarbons have become a larger parcel of the oil and gas market. A variety of techniques are available to provide a satisfactory description of these porous media. Some techniques are based on saturating the porous rock with a fluid to probe the pore structure. In this sense, gases have played an important role in porosity and pore structure characterization, particularly for the analysis of pore size and shapes and storage or intake capacity. In this review, we discuss the use of various gases, with emphasis on N2 and CO2, for characterization of shale pore architecture. We describe the state of the art on the related inversion methods for processing the corresponding isotherms and the procedure to obtain surface area and pore-size distribution. The state of the art is based on the collation of publications in the last 10 years. Limitations of the gas adsorption technique and the associated inversion methods as well as the most suitable scenario for its application are presented in this review. Finally, we discuss the future of gas adsorption for shale characterization, which we believe will rely on hybridization with other techniques to overcome some of the limitations.

This document is the accepted manuscript version of a published work that appeared in final form in Energy and Fuels, © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.6b02112, Moringa oleifera seed shells exhibit a unique structure of cross-linked sub-microfibers (0.5-1.5 μm diameter) with a well-connected macroporous network. Controlled pyrolysis (500-800 °C) and cyclic activation of the precursor provided a porous carbon material with a structure that minimizes mass-transfer constraints. Under both slow (10 °C/min-1) and flash pyrolysis, the structure was preserved, while a significant microporosity was developed. By flash pyrolysis (700-800 °C), a material with enhanced characteristics for potential application as a molecular sieve (SDA = 450-470 m2 g-1, and SBET = 5 m2 g-1) was obtained. Cyclic activation of carbonized shells, consisting of an oxygen chemisorption stage (180 °C) followed by a desorption stage in an inert atmosphere (450-900 °C), resulted in a controlled development of microporosity upon successive activation cycles. After 10 activation cycles, respective SDA and SBET values of 1172 and 761 m2 g-1 were obtained. Higher development of the surface area and a wider distribution of micropores was observed when the desorption stage was carried out at 900 °C. The development of the surface area was achieved at low burnoff (22-33%), thus preserving the structure of the material. Thanks to its unique structure, the material obtained exhibited enhanced characteristics for gas sorption as a result of diminished mass-transfer limitations, assessed through the kinetics of carbon dioxide adsorption runs at ambient conditions, The authors greatly appreciate financial support from the Spanish Ministerio de Economía y Competitividad (CTQ2012-32821)