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In this study, a modified advanced double-layer model based on statistical physics was developed and utilized to explore the adsorption of carbon dioxide (CO 2) on two zeolites: W-ZSM-5 and W-silicalite-1. This model was formulated assuming that different chemical potentials were involved in the interfacial phenomenon, in contrast to other double-layer models that consider only one chemical potential. This formulation provides a better understanding of the multilayer adsorption of gases. The results obtained from this new model indicate that in the case of the CO 2 -W-ZSM-5 system, CO 2 molecules altered their adsorption orientation from a mixed orientation (n = 0.88) involving both parallel and non-parallel configurations. Similarly, the molecules shifted from a multimolecular orientation (n = 1.17) to a perpendicular orientation for CO 2 adsorption on the W-silicalite-1 surface. The calculated adsorption energies confirmed the presence of an exothermic adsorption process governed by physical interactions between the CO 2 molecules and the surfaces of these zeolites. Finally, the adsorption energy distribution (AED) of both adsorbent surfaces was analyzed to determine the energy band activated during the CO 2 capture process. These findings contribute to a deeper understanding of CO 2 adsorption on zeolite surfaces. This new statistical physics model can be used for the process design of gas adsorption systems in various applications. Modeling of CO 2 capture on (a) W-ZSM-5 and (b) W-silicalite-1 via a new double-layer model with separated density of linking sites (Model 3). [Display omitted] • A modified statistical physics model for gas capture is reported. • This model considers two chemical potentials to represent the interfacial phenomenon. • This improved model was tested to explain CO 2 capture using hybrid zeolites. • This improved model offers a better understanding of gas adsorption mechanisms. [ABSTRACT FROM AUTHOR]

In this work, we demonstrate that a simple hydrothermal treatment followed by pyrolysis of regular and diet soft drinks can generate well-defined carbon structures including solid and hollow spheres with a high degree of microporosity. These materials show high and selective CO 2 adsorption with a capacity up to 4.65 mmol g−1 at 0 °C and 1 bar depending on the particular soft drink used as the precursor. Isosteric heats of adsorption ranged from 22.3 kJ mol−1 to 29.2 kJ mol−1 which suggests a relatively low regeneration energy for ease of re-use. Carbon dioxide adsorption cycles were repeated for ten cycles with no loss of capacity confirming the reusability of the carbon. We also explore the effect of artificial sweeteners on the morphology and CO 2 interaction of the resulting carbon materials. These results show that waste soft drinks can be used to create high-value, porous carbon materials for applications such as carbon capture. A simple synthetic procedure can be used to convert waste soft drinks to a valuable porous carbon material that can remove CO2 from waste combustion products. Image 1 • Alternative feedstock for carbon. • Simple synthetic procedure to convert waste soft drinks to porous carbon. • Type of soft drink precursor influences the pore structure of the carbon. • Carbon shows selective separation of CO2 from waste combustion products. [ABSTRACT FROM AUTHOR]

Abstract This review summarizes the latest synthesis methods, characterization and corresponding applications of MOF-74 and its derivatives in recent years. Metal–organic frameworks (MOFs) are nanomaterials with many attractive advantages, such as good stability, large specific surface area and large apertures, which make them receive considerable attention. Among them, MOF-74 is a particularly outstanding one attribute to its excellent CO 2 adsorption capacity. MOF-74 can be synthesized directly from a metal oxide and without bulk solvent, which not only saves a lot of time and money, but also is more ecological. The mesopores in MOF-74 can be adjusted to as large as 15 nm stably at room temperature. And characterization results show MOF-74 possesses good hydrolysis stability, highly stable structure, gas adsorption capacity, catalytic activity and so on. In addition, multifarious synthetic materials with additional functionality can be obtained by properly combining MOF-74 with other components. Therefore, MOF-74 has great potential and has aroused great enthusiasm for research in many aspects, such as gas adsorption, separation, and catalysis and so on. Graphical abstract The biggest highlight of MOF-74 is its excellent carbon dioxide adsorption properties, especially Mg-MOF-74, which is attractive in realizing CO 2 high efficiency and energy saving. The adsorption behavior and mechanism were summarized in detail. In addition, we also introduced the performance of MOF-74 in other gas adsorption, such as H 2 , O 2. New synthetic methods, like directly from a metal oxide, provide more ideas and richer materials for the further research of MOF-74. In addition, the good stability of MOF-74 is of great significance for its wide application. And different kinds of derivatives have great application value in various aspects such as gas adsorption, separation, catalysis, molecular probes, and drug transportation and so on. Image 1 Highlights • New MOF-74 synthesis methods are introduced, which help reduce cost and protect environment. • This review describes the good properties of MOF-74, especially its good stability. • The adsorption behaviors of MOF-74 on various common gases are summarized. • The mechanisms of various reactions of MOF-74 are described. • Many analogues of MOF-74 are introduced, which play an important role in future research. [ABSTRACT FROM AUTHOR]

Abstract A growing interest is currently directed to find an efficient NO and CO 2 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. Graphical abstract Image 1 Highlights • Preparation of colloidally stable Na- and Cu-containing FAU nanozeolite. • Evaluation of CO 2 and NO adsorption properties on metal exchanged FAU. • Cytotoxicity assessment of nanozeolite towards three types of cells. • Verified biocompability of FAU for biomedical (gas delivery) applications. [ABSTRACT FROM AUTHOR]

Abstract In this manuscript, we report synthesis, characterization and application of amine and amide type covalent organic frameworks as CO 2 adsorbent materials at various isotherms and wide pressure conditions. Furthermore, we also report a detailed density functional theory investigation of the studied adsorbents in order to explain their adsorption behaviors and provide comparisons with experimental results. The objective of this work was to investigate custom design porous polymers by building amine and amide functionalities in the final structures, whether they have efficient CO 2 capturing performances at wide process conditions that covers both low and high pressure end applications to cover either pre- or post-combustion processes. On the other hand, energy storage performances of these materials were tested by performing H 2 sorption experiments as well. Two porous polymers, namely COP-9 and COP-10, were characterized with BET, TGA and FTIR to evaluate the physical properties of studied porous polymers and then were tested for CO 2 , N 2 and H 2 adsorption both at low and high pressures. Studied materials were found to have compelling adsorption capacity mostly at high pressures and have very good selectivity for CO 2 /N 2 and CO 2 /H 2 respectively. Graphical abstract Image 1 Highlights • Covalent organic polymers were studied by using both experimental and theoretical techniques (DFT). • High CO 2 sorption performance at high pressures. • Good CO2/N2 selectivity at lower pressures. • DFT results confirmed the experiments and provided insights on active adsorption sites with atom in a molecule study. [ABSTRACT FROM AUTHOR]

Abstract The porosity of clay minerals is dominated by nanoscale pores that provide a large surface area for physical and chemical interactions with the surrounding fluids, including gas adsorption. Measuring gas adsorption at subsurface conditions is difficult, because elevated pressures are required and the interactions between the supercritical gas and the clay are relatively weak. Here, we report on the measurement of adsorption isotherms of CO 2 and CH 4 on the source clay Na-montmorillonite (SWy-2) at different temperatures (25–115°C) over a wide range of pressures (0.02–25 MPa). The experimental observations are thoroughly analysed by considering both net and excess adsorbed amounts, and by extracting adsorption metrics, such as the Henry's constants and enthalpy of adsorption. The results consistently indicate that SWy-2 favours adsorption of CO 2 over CH 4 with selectivity, S ≈ 5.5. The experimental data are successfully described using a Lattice Density Functional Theory (LDFT) model. The adsorption energetics estimated by the model compare well with the experimentally obtained enthalpy of adsorption. It is further shown that even at the highest pressure the pore space of the clay is only partially filled and that the degree of saturation increases upon approaching the critical temperature of the gas. The ability of the LDFT model to reveal pore-dependent adsorption behaviours demonstrates its potential against empirical models, such as the Langmuir equation, which fail at capturing the complexities of supercritical gas adsorption at subsurface conditions. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Two new porous coordination polymers, [Co 3 (μ 3 -OH)(Bcb10DC) 2.5 (DEF) 3 (EtOH) 1.5 (H 2 O) 0.5 ] · DEF · EtOH ( 3b ) and [Co 2 (Bcb12DC) 2 (DMF) 4 (EtOH)] · 2EtOH ( 4 ) based on 10- and 12-vertex p- bicarboranedicarboxylic acids, 1,1′-bi-(1,10-dicarba- closo -decaborane)-10,10′-dicarboxylic acid (H 2 Bcb10DC) and 1,1′-bi-(1,12-dicarba- closo -decaborane)-12,12′-dicarboxylic acid (H 2 Bcb12DC) were synthesized. Their properties were compared with the two known analogues based on shorter ligand-homologues, [Co(cb10DC)(DMF)] ( 1 ) and [Co 4 (OH) 2 (cb12DC) 3 (DMF) 2 (H 2 O) 4 ] · 3DMF · EtOH ( 2 ). The structure of 3b is based on a trinuclear cluster and has a 3D structure with a 5-c bnn underlying net, while 4 is based on a binuclear cluster and composed of stacked 2D sql layers. Activated 3′ with altered structure has S BET (N 2 ) of 1012 m 2  g −1 and 4′ with mostly retained structure 920 m 2 g −1 . Gas adsorption by 3′ and 4′ at 1 bar is: 80.1 cm 3  g -1 (0.72% wt ) and 81.3 cm 3  g -1 (0.73% wt ) H 2 at 77 K; 16.7 and 21.9 cm 3  g -1 CO 2 at 273 K; 6.2 and 10.0 cm 3  g -1 of CH 4 at 273 K. The isosteric heat of adsorption Q st at zero coverage are respectively: 5.0 and 4.5  kJ mol −1 for H 2 , 16.7 and 21.9 for CO 2 ; 6.2 and 10.0 for CH 4 . 2′ with ∼ 645 m 2  g −1 (calc. 883 m 2 g −1 ) has the highest mass-specific H 2 adsorption, >30% than other compounds, while Q st is close to 1′ and slightly higher than for 3′ and 4´ . Adsorption of CO 2 and CH 4 and Q st are ∼1.5–2 times lower for 3′ and 4′ compared to 1′ and 2´ . The surface area specific adsorption of H 2 , CO 2 and CH 4 is the highest for 1´ . The CO 2 /CH 4 IAST selectivities (0.15/0.85; 1 bar, 298 K) are in 2–4.5 range. 3′ and 4′ retain a significant part of porosity after soaking in water unlike 1′ and 2´ . [ABSTRACT FROM AUTHOR]

Resorcinol-formaldehyde aerogel and xerogel were tested as selective adsorbents of hexane isomers under static and dynamic conditions. The aim of this work is to further study the carbon molecular sieve behaviour of some of these samples for linear and branched hydrocarbons separation in gas phase, and the possibility of tuning the adsorptive properties of the xerogel by means of physical activation with carbon dioxide. While the aerogel presented a larger micropore volume, the micropore mean width was narrower than in the case of the xerogel, therefore its behaviour as selective adsorbent of n- hexane was better; in fact, equilibrium adsorption demonstrated that the carbon aerogel acts as a carbon molecular sieve with respect to the four isomers tested, being able to separate all of them. The ratio for adsorbed amounts at saturation obtained from Langmuir resulted 16.1 for n-hexane, 4.4 for 3-methylpentane and 2.2 for 2,3-dimethylbutane compared with the one for 2,2′-dimethylbutane. These values decreased significantly when xerogel was used as adsorbent (1.7 for n-hexane, 1.5 for 3-methylpentane and 1.3 for 2,3-dimethylbutane) and for the carbon dioxide activated samples. In such a way, when adsorption equilibrium isotherms for the four isomers onto the adsorbent with a highly developed microporosity (activated up to 40%) were assessed, there were almost no differences between them. The excellent performance of the aerogel in the separation of n-hexane and 2,2′-dimethylbutane was finally proven by competitive dynamic adsorption experiments, while the carbon dioxide activated samples showed great potential for VOCs removal due to their enhanced capacity. [ABSTRACT FROM AUTHOR]

Heteroatom-doped porous carbons have attracted great concern owing to their enhanced physicochemical property. In this study, a hierarchically porous sulfur- and oxygen-co-doped carbon (PSOC) is obtained through direct carbon dioxide activation of poly(3,4-ethylenedioxythiophene) with abundant sulfur and oxygen atoms in the polymer backbone. Both sulfur and oxygen heteroatoms are introduced into carbon matrix through a rational preparation approach. The morphology, microstructure, and chemical property of the as-prepared PSOC have been analyzed by using various characterization methods, including scanning/transmission electron microscopy, nitrogen sorption test, Raman spectroscopy, and X-ray photoelectron spectroscopy. PSOC displays a high specific surface area (1160 m 2  g −1 ) and hierarchically porous structure (micropores, mesopores, and macropores). Owing to its excellent surface property and porosity parameters, PSOC exhibits a good gas adsorption capacity (carbon dioxide: 16.6 wt %; methane: 2.7 wt %) at 273 K under 1.0 bar when used as a gas sorbent. In addition, PSOC as an anode material shows a high reversible capacity of 931 mA h g −1 at 100 mA g −1 and excellent cycling performance (504 mA h g −1 at 200 mA g −1 after 200 cycles). As a result, the as-prepared PSOC demonstrates a promising potential in the fields of gas adsorption and energy storage. [ABSTRACT FROM AUTHOR]

Graphene oxide/ordered mesoporous carbon (GO/OMC) nanostructures with narrow mesopore size distribution were obtained via soft-templating synthesis followed by KOH activation. Microporosity and mesoporosity of these composite nanostructures were additionally controlled by adjusting the amount of added GO and by post-synthesis KOH activation. Incorporation of GO into OMC structure resulted in improving adsorption uptakes of benzene and hydrogen, which reached 9.6 mmol/g (at 20 °C and pressure close to the saturation vapor pressure) and 11.7 mmol/g (2.3 wt% H 2 at −196 °C and 760 mm Hg), respectively. At the same conditions bare activated OMC adsorbed 8.1 mmol/g and 10.8 mmol/g of benzene and hydrogen, respectively. Also, these adsorbents showed high uptakes of CH 4 (2.1 mmol/g at 20 °C and 760 mm Hg) and CO 2 (6.0 mmol/g at 0 °C and 760 mm Hg). The GO/OMC composite nanostructures were characterized by nitrogen adsorption, scanning electron microscopy, Raman spectroscopy and thermogravimetry. To the best of our knowledge, this work represents the first comparative study of adsorption properties of the GO/OMC composite nanostructures toward various gases. [ABSTRACT FROM AUTHOR]

Microwave-assisted synthesis of zirconium (Zr) based metal organic frameworks (MOFs) were performed and the yield and porous property of UiO-67 was optimized by varying the quantity of the modulator (benzoic acid, BenAc and hydrochloric acid, HCl), reaction time and temperature. It was found that ( i ) an increase in the amount of modulator enhanced the specific surface area and pore volume of UiO-67 due to the promotion of linker deficiency; and ( ii ) the presence of modulators influenced the number of nuclei (and hence the crystal size) and nucleation time (and hence the yield). Optimum amounts of BenAc and HCl for synthesizing UiO-67 under microwave irradiation were determined as 40 mol equivalent and 185 mol equivalent (to Zr salt), respectively. In comparison to conventional solvothermal synthesis, which normally takes 24 h, microwave methods promoted faster syntheses with a reaction time of 2–2.5 h (at similar temperatures of 120 °C and 80 °C for BenAc and HCl, respectively). The thermal effect of microwave is believed to contribute to the fast synthesis of UiO-67 in the microwave-assisted synthesis. The reaction mass efficiency and space-time yield show that microwave heating promoted the simple yet highly efficient preparation of Zr-based MOFs. In addition, UiO-67 MOFs from different synthesis methods ( i.e. the microwave-assisted and solvothermal method) were evaluated using single-component (CO 2 and CH 4 ) adsorption, showing comparable gas uptakes. [ABSTRACT FROM AUTHOR]

Pillared Graphene Frameworks are a novel class of microporous materials made by graphene sheets separated by organic spacers. One of their main features is that the pillar type and density can be chosen to tune the material properties. In this work, we present a computer simulation study of adsorption and dynamics of H 2 , CH 4 , CO 2 , N 2 and O 2 and binary mixtures thereof, in Pillared Graphene Frameworks with nitrogen-containing organic spacers. In general, we find that pillar density plays the most important role in determining gas adsorption. In the low-pressure regime ( ≲ 10 bar) the amount of gas adsorbed is an increasing function of pillar density. At higher pressure the opposite trend is observed. Diffusion coefficients were computed for representative structures taking into account the framework flexibility that is essential for assessing the dynamical properties of the adsorbed gases. Good performance for the gas separation in CH 4 /H 2 , CO 2 /H 2 and CO 2 /N 2 mixtures was found, with values comparable to those of metal-organic frameworks and zeolites. [ABSTRACT FROM AUTHOR]

The sustainable capture and sequestration of CO 2 from flue gas emission is an important and unavoidable challenge to control greenhouse gas release and climate change. In this report, we describe a triazine-triphenylamine-based microporous covalent organic polymer under mild synthetic conditions. 13 C and 15 N solid-state NMR and FTIR analyses confirm the linkage of the triazine and triphenylamine components in the porous polymer skeleton. The material is composed of spherical particles 1.0 to 2.0 μm in size and possesses a high surface area (1104 m 2 /g). The material exhibits superb chemical robustness under acidic and basic conditions and high thermal stability. Single-component gas adsorption exhibits an enhanced CO 2 uptake of 3.12 mmol/g coupled with high sorption selectivity for CO 2 /N 2 of 64 at 273 K and 1 bar, whereas the binary gas mixture breakthrough study using a model flue gas composition at 298 K shows a high CO 2 /N 2 selectivity of 58. The enhanced performance is attributed to the high Lewis basicity of the framework, as it favors the interaction with CO 2 . [ABSTRACT FROM AUTHOR]

We developed a facile and universal method for synthesizing ordered mesoporous hydrothermal carbon materials from saccharides through a modified soft-templating approach. In a typical process, the micelles formed during the dissolving process of triblock copolymer and acted as soft template. Then, in order to avoid the destruction of the micelles during the following hydrothermal carbonization process, the micelles were covered and stabilized by silica layer, which is formed by hydrolysis of tetraethyl orthosilicate and subsequent condensation reaction of the formed orthosilicic acid. During the hydrothermal carbonization process, the saccharides-derived hydrothermal carbon will form on the surface of silica layer. After removal of the modified soft template, ordered hydrothermal carbon materials were obtained. The ordered structure was confirmed by transmission electron microscopy and small-angle X-ray diffraction technique. The Brunauer‒Emmett‒Teller specific surface area values of the as-prepared ordered hydrothermal carbon materials range from 330 to 620 m 2 g −1 . It is worth to mention that it is a universal method for transforming different saccharides, such as glucose, D-fructose, D-maltose, sucrose, and β-cyclodextrin, into ordered mesoporous hydrothermal carbon materials. [ABSTRACT FROM AUTHOR]

Six new lanthanide metal organic complexes, i.e. [La 2 (NO 2 -BDC) 3 (H 2 O) 4 ] (1) [Ln(L) 0.5 (NO 2 -BDC) (H 2 O)]·3H 2 O (Ln = Eu ( 2 ), Tb ( 3 ), Dy ( 4 ) and Ho ( 5 ); L = BDC 2− or BDC 2− /NO 2 -BDC 2- ) and [Tm(NO 2 -BDC) 1.5 (H 2 O)]·H 2 O ( 6 ), have been synthesized using mixed ligands of benzene-1,4-dicarboxylic acid (H 2 BDC) and the in situ generated 2-nitro-benzene-1,4-dicarboxylic acid (NO 2 -BDC 2- ). Single crystal structures and topologies of the complexes are presented based on the single crystal X-ray diffraction and spectroscopic data. Whilst the structures of 1 and 6 contain negligible voids, the frameworks of 2 – 5 are microporous in nature and stable upon the removal of all the water molecules from the structures and thermal treatment to over 400 °C. Based on the study of 2 , significant adsorption capacities for carbon dioxide (95 cm 3 ·g −1 or 4.2 mmol·g −1 ) and hydrogen (79 cm 3 ·g −1 or 4 mmol·g −1 ), as well as the remarkable stability of the framework upon the sorption/desorption experiments are revealed. [ABSTRACT FROM AUTHOR]

Two kinds of POSS-based microporous organic polymers (PMOPs) were prepared by cost-effective Friedel-Crafts reaction of octaphenylsilsesquioxanes with p -dimethoxybenzene (PMOP-1) or cyanuric chloride (PMOP-2). PMOP-1 with high surface area of 806 m 2 g −1 exhibited reasonable CO 2 adsorption (2.59 mmol g −1 , 273 K/1 bar) and selectivity, whereas PMOP-2 with lower surface area (559 m 2 g −1 ) showed a higher CO 2 /N 2 selectivity (30.0) and CO 2 /CH 4 selectivity (6.8) at 273 K/1 bar due to the high amount of nitrogen incorporated within the structure. The correlation between the performance of PMOPs in CO 2 capture/separation and their properties such as surface area, surface active sites, and heat of adsorption was investigated. The combination of a cost-effective method, high thermal stability, and reasonable selective adsorption make these materials potential candidates for application in CO 2 capture and separation technology. [ABSTRACT FROM AUTHOR]

The three dimensional KIT-6 with interconnected mesoporous was synthesized using triblock copolymer (P123) in mild acidic condition. The hydrothermal, thermal, mechanical and hydrolytic stability of KIT-6 were comprehensively investigated by N 2 adsorption/desorption, small-angle X-ray scattering and electron micrograph. In the initial stage of synthesis, washing of as-synthesized KIT-6 with water improves the textural property such as surface area and pore volume. The size of primary mesopores and pore volume of the material could be tailored by ageing the solution without any loss in structural morphology. KIT-6 shows the high mechanical stability up-to 4680 bar and preserves its mesopore surface area possibly due to the presence of thicker pore wall and cubical structure. KIT-6 shows the gradual decrease in surface area, pore volume and diameter with increasing calcination temperature from 823 to 1173 K, due to sintering/shrinkage of silica structure. It also shows the stable structural properties even after ageing for 6 months in atmospheric conditions and 1 month in water at room temperature. However, after 3 days of ageing in boiling water, KIT-6 still retains its porosity. In presence of ultra-high pressure, CO 2 shows good surface interaction towards KIT-6 with sorption capacity of 1.42 mol/kg (1 bar) and 10.1 mol/kg (20 bar) at 273 K without significant damage to its structure. Additionally, it also shows 2.38 wt% H 2 storage capacity at 30 bar and 77 K. The highly stable KIT-6 is considered to be a good material for catalyst support, nano structure, CO 2 separation and H 2 storage. [ABSTRACT FROM AUTHOR]

Nanocrystalline Zeolite-Y having large internal and external surface area due to its nanometer scale crystals are applied for catalysis and separation processes. In this study, a novel approach for the preparation of uniform size Zeolite-Y nanocrystals from concentrated colloidal solution system is explored. The synthesis composition systems studied were concentrated solutions with high amount of organic template to give a large number of nuclei resulting in formation of uniform size nanocrystalline Zeolite-Y. The nanocrystalline Zeolite-Y of uniform particle sizes ca. 40 nm was successfully synthesized. The nanocrystalline Zeolite-Y synthesized in present study had excellent pore volume of ca. 0.91 cm 3 /g which is about three times than the pore volume obtained by conventional microcrystalline Zeolite-Y. A decrease in the organic template content resulted into the Zeolite-Y crystals of bigger size up to 60 nm along with some presence of Zeolite-A as impurity. The gas adsorption study of O 2 , N 2 , CO 2 , and CH 4 were performed on these nanocrystalline zeolites and their gas separation properties were analysed. A strong CO 2 interaction with the nanocrystalline Zeolite-Y was observed according to the adsorption model expressed by Toth equation. CO 2 /N 2 selectivity and CO 2 /CH 4 selectivity of ca. 300 were observed at lower relative pressure for the nanocrystalline Zeolite-Y which shows potential as promising material for application in CO 2 separation of flue gas from thermal power plant and natural gas purification. [ABSTRACT FROM AUTHOR]

An original method for porosity assessment is proposed, which uses gas injection into dried or partially-dried claystone under hydrostatic stress. For these materials, accurate porosity assessment is complicated by the interactions of clay with water, by its crack sensitivity and by the fineness of the pores (ranging from a few nm to hundreds of nm). The hydrostatic stress limits the sample volume changes and favors crack closure. Our method is compared with water vapor equilibration or injection, with ethanol injection, and tested with two different gases (argon and helium). It is applied to COx claystone from five different cores and to a sandstone devoid of swelling clay. In addition, relative pore volumes for partially water-saturated rock are obtained. Contrarily to helium pycnometry, this method may be coupled with fluid transport assessment. Contrarily to sandstone, a significantly greater porosity is obtained for dry COx claystone with argon gas injection, when compared to water, ethanol or helium gas. The adsorption of argon gas on the surface of clay particles is attested as the main phenomenon responsible for these differences. Hydrostatic stress, sample drying temperature (65 or 105 o C) and sample thickness do not affect results significantly. For partially water-saturated claystone, the total porosity measured by gas injection is adequate with argon or helium, but only in a given relative humidity ( RH ) range ( RH = [0;85%] for helium, and RH = [40;75%] for argon). Argon adsorption and a limited accessibility of gas to the pore network in highly saturated medium explain these limits. [ABSTRACT FROM AUTHOR]

Two new microporous metal-organic framework materials constructed from Zr(IV) ( 1 ) or Ce(IV) ( 2 ) ions and 4-carboxycinnamate (CCA) ligand are presented. 1 was prepared by heating a mixture of ZrCl 4 , H 2 CCA ligand and acetic acid with a molar ratio of 1:1:10 in N,N ′-dimethylformamide (DMF) at 150 °C for 24 h. 2 was synthesized by solvothermal reaction of a mixture of ammonium cerium(IV) nitrate and H 2 CCA ligand in a DMF/H 2 O mixture at 100 °C for 20 min. The as-synthesized and the thermally activated forms ( 1′ and 2′ ) of the compounds were characterized by X-ray powder diffraction (XRPD), Fourier transform infrared (FT-IR), thermogravimetric (TG) and elemental analysis. 1 and 2 show high thermal stability up to 390 and 300 °C in air atmosphere, respectively. According to XRPD measurements, both compounds show moderate stability in water, but they lose their crystallinity in 1 M HCl. N 2 sorption experiments reveal that 1′ and 2′ possess BET surface areas of 870 and 1210 m 2 g −1 , respectively. The CO 2 uptake values of 1′ and 2′ at 0 °C and 1 bar are 2.0 and 1.6 mmol g −1 , respectively. [ABSTRACT FROM AUTHOR]

Ethane is rapidly becoming an efficient and dependable clean energy source for fast-growing and developing countries. It is the second most abundant natural gas after methane. However, it poses a major problem for ozone pollution and plays a significant role in greenhouse warming once released into the atmosphere. Therefore, understanding the mechanisms that govern its behavior during storage in natural and artificial nanoporous materials is essential for numerous industrial and environmental applications. In this work, the confined phase behavior of ethane was investigated in ordered mesoporous silica material MCM-41 at varying nanoscale-pore sizes and temperatures. Adsorption and desorption isotherms were experimentally measured for a wide range of nanopore diameters (7, 10.2, 11.3, and 12.3 nm) and temperatures (varying from −65 to −20 °C) using an automated gravimetric nanocondensation apparatus. This system enabled direct quantification of the mass of ethane adsorbed onto the surfaces of nanopores. We examined the impact of the pore diameter and temperature on the adsorption, capillary condensation, and evaporation of ethane in nanoporous media. The capillary condensation and evaporation pressures were determined using the Lorentzian functions. The accuracy of the measurements was confirmed by comparing the experimental bulk condensation pressures with those reported by the National Institute of Standards and Technology (NIST). The results demonstrate that the capillary condensation pressures increased with ascending pore diameters and temperatures. They also indicate that the degree of suppression of the saturation pressure due to confinement is predominant at low temperatures. The percent reduction in the pressure of vapor-liquid phase change decreased with an increase in temperature. A similar trend was observed with respect to changes in the pore size. The results showed that the effect of confinement was weakened as the nanopores became wider. Furthermore, insights were developed about the effects of pore diameter and temperature on the occurrence of the supercritical-like behavior of ethane in nanopores. A good agreement was evident between our results and the examples available in the literature. To the best of our knowledge, we present the first experimental study that describes the confined phase behavior of ethane using a patented gravimetric apparatus. This work presents a systematic approach to understand the effects of confinement in nanoporous media. Furthermore, it can aid the development of new ethane storage applications, especially the characterization of natural and artificial porous materials for energy and environment-related solutions. [Display omitted] • Effect of nanoconfinement was probed on the phase properties of ethane in mesoporous material MCM-41. • Experiments were conducted at varying temperatures and pore diameters using a patented gravimetric approach. • Results indicate that nanoconfinement effect is predominant in small nanopores due to enhanced solid-fluid interactions. • The capillary condensation pressure increases with ascending pore size and temperature. • The suppression of vapor-liquid phase transition pressure decreases with an increase in the pore diameter. [ABSTRACT FROM AUTHOR]

Five new coordination polymers [Zn 3 (biimb) 2 (BPT) 2 ]·4DMF·2.5H 2 O ( 1 ), [Zn(biimb)(NDC)]·1.5H 2 O ( 2 ), [Zn(biimb)(NDC)]·3DMF ( 3 ), [Cd(biimb)(NDC) 0.5 Cl]·3H 2 O ( 4 ) and [Cd 3 (biimb) 2 (BPDC) 3 (H 2 O) 4 ]·4H 2 O ( 5 ) [biimb = 1,3-bis(1-imidazolyl)-5-(imidazol-1-ylmethyl)benzene, H 3 BPT = biphenyl-3,4′,5-tricarboxylic acid, H 2 NDC = 2,6-naphthalenedicarboxylic acid, H 2 BPDC = 4,4′-biphenyldicarboxylic acid, DMF = N , N -dimethylformamide] were synthesized by hydro/solvothermal reactions and characterized by elemental, thermogravimetric analyses, IR, powder and single crystal X-ray diffractions. Complex 1 is a (3,3,4,4)-connected 4-nodal 3D framework. The linkage of Zn(II), biimb and NDC 2− makes a 2D network structure of 2 , in which biimb acts as a bidentate ligand, while in 3 , the biimb ligands display as tridentate and connect Zn(II) to compose 2D networks, which are further linked together by NDC 2− to generate 3D structure of 3 . 4 is a pillared-layer 3D net containing [Cd(biimb)Cl] + layers and NDC 2− pillars. 5 is an interesting 3-fold interpenetrating 3D net. Photoluminescence and gas adsorption properties of the complexes were investigated. [ABSTRACT FROM AUTHOR]

The spinel NiCo 2 O 4 has been prepared as a powder and a film by three common techniques: thermal decomposition, co-precipitation and spray pyrolysis. The porous nature of these materials has been investigated by a combination of nitrogen adsorption and mercury intrusion porosimetry. It is shown that thermal decomposition yields a material of low meso-porosity with the majority of pores being confined to the macropore region. Both co-precipitation and spray pyrolysis yield powders of appreciable BET surface area and meso-porosity in a mono-modal distribution. The pore size distributions indicate smaller pores in the case of the co-precipitated sample. The preparation of films by co-precipitation and spray pyrolysis is shown to introduce a second region of meso-porosity. The deposition of co-precipitated powder as a film is investigated through the addition of a PTFE binder with and without a pressing step in the process. Porosity is shown to decrease through the addition of PTFE with no pressing and decrease further again when the film is subjected to pressing. [ABSTRACT FROM AUTHOR]

All 229 identified zeotype frameworks are screened in their siliceous form by grand canonical Monte Carlo simulation for their ability to separate a radiochemically relevant Kr/Xe mixture in a pressure swing adsorption process. Prior to screening, our model was benchmarked against experimental single gas adsorption measurements, and it was found that for Kr and Xe a Lennard-Jones 9-6 potential with a softer repulsion than an equivalently parameterized Lennard-Jones 12-6 potential was necessary to accurately model fluid–fluid interactions. Examination of the most promising candidate materials, we concluded that zeolites with small, accessible cages about the size of a Xe atom performed the best initially. Zeolites with narrow pore channels with spots along the pore wall with high local surface area are the best performers across all loadings. [ABSTRACT FROM AUTHOR]

Natural and synthetic zeolites have wide use industry and in many other applications as food additives, as molecular sieve to trap unwanted ingredients like heavy metallic ions and groups in fluids, as shielding materials against high energy radiations etc. Clinoptilolite is a type of zeolite composed of aluminasilicate forming tetrahedrons with micro cavities among them. The size and shape of cavities, impurities and the metal ions define their usage. Electron paramagnetic resonance (EPR) spectroscopy is a technique to determine paramagnetic species in host materials, and hence in the zeolites and clay type minerals. In this study natural clinoptilolite obtained from Bigadiç district in Western Anatolia, was studied using EPR spectroscopy in natural form and after some physical and chemical treatments, namely adsorbing CO 2 , H 2 S, and SO 2 gases, [Cu(H 2 O) 6 ] 2+ ions and after exposing to gamma rays. The clinoptilolite including non-paramagnetic manganese ions as impurities in natural form reduced to paramagnetic Mn 2+ ions after CO 2 and H 2 S adsorption, and when SO 2 gas is adsorbed an unstable paramagnetic center was induced which changed with time when stored at room temperature. When Cu(H 2 O) 6 was adsorbed Cu 2+ ion complex was adsorbed in the cavity in slightly distorted octahedral structure. Gamma ray irradiation of clinoptilolite from Co-60 source produced anisotropic o 2 3 − radical ion. [ABSTRACT FROM AUTHOR]

The synthesis of seven new functionalized aluminum terephthalates [Al 3 OCl(DEF) 2 (BDC-X) 3 ] (DEF = N,N -diethylformamide; BDC = 1,4-benzene-dicarboxylate; X = –CH 3 , 1–CH 3 ; –NO 2 , 2–NO 2 ; –OCH 3 , 3–OCH 3 ; –C 6 H 4 , 4–C 6 H 4 ; –F 2 , 5–F 2 ; –(CH 3 ) 2 , 6-(CH 3 ) 2 , –(OCH 3 ) 2 , 7–(OCH 3 ) 2 ) having MIL-101 framework topology was carried out under solvothermal conditions (130 °C, 3–12 h) with conventional electric (CE) heating by using stochiometric mixtures of Al(ClO 4 ) 3 ·9H 2 O and H 2 BDC-X linkers in DEF. The previously reported Al-MIL-101–NH 2 compound was also prepared under similar solvothermal conditions. Moreover, four of the compounds, namely 1–CH 3 , 3–OCH 3 , 4–C 6 H 4 and 7–(OCH 3 ) 2 , was synthesized under microwave-assisted solvothermal conditions (170 °C, 10 min, 150 W) by using similar reaction mixtures as the syntheses with CE heating. The compounds were fully characterized by X-ray powder diffraction (XRPD), Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric (TG) and elemental analysis. The thermally activated forms of the as-synthesized compounds were obtained by exchange of the guest molecules with methanol, followed by heating the methanol-exchanged solids under dynamic vacuum. TG analyses carried out with the thermally activated compounds suggest high thermal stability up to 260–430 °C in an air atmosphere. All of the thermally activated compounds exhibit significant porosity, as confirmed by N 2 and CO 2 sorption experiments. The specific BET surface areas of the compounds fall in the 1328–2398 m 2 g −1 range. The CO 2 uptake values of the compounds lie in the 1.6–3.0 mmol g −1 range at 0 °C and 1 bar. The N 2 adsorption capacities of the compounds are dependent on the size of the attached functional groups. On the other hand, the CO 2 uptake values are dependent both on the size and the nature of functional groups attached to the terephthalate linker molecules. [ABSTRACT FROM AUTHOR]

With a view to producing thick and very high surface area microporous silicon layers (and subsequently powders) by electrochemical anodisation, the incorporation of various types of chemical additives has been investigated, these in combination with hydrofluoric acid electrolyte and high-resistivity p-type parent substrates. Comparison under constant charge conditions shows that anodisation using 50 wt% hydrofluoric acid, or inclusion of the additives hydrochloric acid, sulphuric acid, or ammonium dodecylsulfate with lower concentration hydrofluoric acid, can facilitate powders with internal surface areas of up to 864 m 2 /g, average pore sizes in the region of 2.8–3.2 nm, and pore volumes in excess of 0.8 cm 3 /g – all as determined using nitrogen gas adsorption and associated isotherm analysis. Porous silicon powders with appreciable micropore content have thus been achieved, for the first time. Relevant application areas for such material are diverse, and potentially include energetics, impurity gettering, gas sensing microchips, orthopaedic implants, hydrogen storage, and Li-ion battery anodes. [ABSTRACT FROM AUTHOR]

Highlights: [•] New family of rare-earth bearing porous metal organic frameworks. [•] Multifunctional exhibiting porosity and photoluminescence with high quantum efficiency. [•] Selective adsorption of CO2 from CH4 and C2H6. [•] The single crystal photoluminescence indicating strong optical anisotropy. [•] The photoluminescence varied upon rehydration and dehydration. [Copyright &y& Elsevier]

Complex large models of multi-scale microstructures of porous media do not exist in a manner adequately efficient to render their comprehensive analysis of textural and structural properties possible. The simulation of experimental processes, such as gas adsorption, raises two issues. First, the modeling of these complex materials must be sufficiently realistic. This implies that the numerical twin of the porous material must consider three essential aspects: a spatial structure defining different scales of porosity, comparable textural and structural properties of the real material and irregular pore morphology. Secondly, efficient algorithms must be developed to mimic the quasi-static phase transition behavior of fluids in a realistic manner. The proposed simulation approach allows to handle the physico-chemical phenomena inside complex materials by means of well-established mathematical operators. Morphological operators are used to efficiently mimic processes such as surface adsorption and pore filling. Fluid percolation that provokes phase transition is simulated by labeled connected components. This method relies entirely on morphological and structural operators, which has the advantage of substantially reducing the calculation time compared to that of density functional theory and molecular simulations-based approaches. In contrast to oversimplified models characterized by ideal pore shape and unconnected pores, our approach enables us to calculate the adsorption isotherm of realistic random models where pore morphology and porous network topology are unknown beforehand. We demonstrate that our model succeed in reproducing the adsorption isotherm of two well-known model materials (SBA-15 and KIT-5) and mesoporous alumina, represented by Cox Boolean models. [Display omitted] • Morphological operators allow mimicking the processes of gas adsorption. • The presented method is not time consuming and handles realistic models of porous media. • The obtained adsorption isotherms of SBA-15, KIT-5 and mesoporous alumina are close to the experimental curves. [ABSTRACT FROM AUTHOR]

Lanthanum microporous frameworks (Hdma) 2n [La 2 (1,3-pdta) 2 (H 2 O) 2 ] n ·5nH 2 O (1 , dma = dimethylamine, 1,3-pdta = 1,3-propanediaminetetraacetic acid) and (H 2 pn) n [La 2 (1,3-pdta) 2 (H 2 O) 2 ] n ·5nH 2 O (2 , pn = 1,3-propanediamine) with double channels have been template-synthesized by protonated dimethylamines and 1,3-propanediamines, respectively. While bulky product (H 2 bn)[La 2 (1,3-pdta) 2 (H 2 O) 4 ]·10H 2 O (3 , bn = 1,4-butanediamine) is isolated as a dinuclear species with tetrahydrates, whose main anion can be served as a precursor for 1 and 2. Materials 1 – 3 are able to maintain their chemical and thermal stabilities to 200 °C based on TG and XRD analyses. Gas adsorptions demonstrate that MOFs 1 and 2 are amicable for O 2 and CO 2 , while no adsorption has been observed for CH 4 , N 2 or H 2 respectively. The amounts of encapsulated CO 2 in hydrophobic pores are dependent on the alkalinities of the diamines in the next confined hydrophilic holes, showing synergistic effects between double channels. For protonated dimethylamines and 1,3-propanediamines in 1 and 2 , obvious downfield shifts have been found by solid-state 13C NMR spectroscopies, along with clear red shifts in FT-IR spectra compared with free species. Moreover, captured CO 2 inside 1 can be quantized by NMR measurements and IR spectroscopies under ambient condition. These all reflect the confinement effects of nano-environments. [Display omitted] • Synergistic and confined effects in lanthanide MOFs with gases are quantized and discussed. • An interesting precursor is obtained when the synthetic template is 1,4-butanediamine. • CO 2 uptake and conversion in the hydrophobic channels can also be spectroscopic characterized. [ABSTRACT FROM AUTHOR]

Highlights: [•] Five metal coordination polymers (MCPs) were synthesized. [•] The organic ligands tuned the structures and topologies of the five MCPs. [•] Five MCPs feature three different type nets: 4×4 sheet, bcg or bcu. [ABSTRACT FROM AUTHOR]

Abstract: Grand canonical Monte Carlo simulations were used to calculate hydrogen adsorption in IRMOF-16, NU-100, and UiO-68 functionalized with Mg or Fe catecholates on the linkers. We examined how altering the number of metal catecholate groups affects H2 uptake and deliverable capacity near ambient temperature. We find that large free volume and an isosteric heat of adsorption (Q st) of 20kJmol−1 at low loading will maximize gravimetric deliverable capacity while a small pore diameter will maximize volumetric deliverable capacity. This suggests a trade-off between the properties that lead to maximal gravimetric and volumetric capacities. For example, our calculations suggest that NU-100 functionalized with six Fe catecholate groups per linker takes up 5.5wt.% deliverable H2 at 243K and 100bar, but only 24.2gL−1 deliverable H2. [Copyright &y& Elsevier]

Abstract: The microporous coordination polymer CPO-27-Fe was synthesized from iron salts and 2,5-dihydroxyterephthalic acid by microwave assisted solvothermal synthesis. The crystal structures of the as-synthesized compounds were determined by Rietveld refinement from powder X-ray diffraction data using synchrotron radiation, revealing a honeycomb-type framework, isostructural to the other compounds in the CPO-27-M series. Exposure to oxygen was found to have pronounced effects on the material, like change of color, band gap, and structural details which we associate with oxidation of the iron(II) in the M2(dhtp) framework to iron(III). XPS measurements confirm the presence of iron in these oxidation states in the respective compounds. The desolvation process of CPO-27-Fe was investigated using variable temperature powder X-ray diffraction and mass spectrometry. CPO-27-Fe passes through several phase transitions when heated up during which it reversibly changes between oxidation states +2 and +3, remaining in divalent state in the empty framework structure Fe2(dhtp) in the last crystalline phase. These measurements also indicate that methanol contained in the pore after synthesis is transformed into formaldehyde during the heating process, potentially making CPO-27-Fe a viable catalyst in redox processes. The effect of the extraordinary high concentration of accessible open metal sites in the desolvated CPO-27-Fe was investigated by gas adsorption experiments using hydrogen, carbon dioxide and oxygen. Oxygen adsorption was reversible at low temperatures, but exposure to oxygen at room temperature led to blocking of the open metal site and partial deconstruction of the framework. Significantly larger amounts of oxygen than nitrogen are adsorbed at room temperature. [Copyright &y& Elsevier]

Abstract: The large pore vanadium(III) trimesate MIL-100(V), i.e. V3O(H2O)2X[C9H3O6]2·yH2O with , y ≈3 and z ≈0.3, has been synthesized under hydrothermal conditions (MIL stands for Materials from Institute Lavoisier). Its structure, which crystallizes in the space group Fd-3m (No.227) with a =73.0286(2)Å, V =389474.4(2)Å3, exhibits a zeotype architecture with mesoporous cages of approx. 25 and 29Å diameter, accessible through microporous windows of 5.5 and 8.9Å diameter. Synchrotron X-ray powder diffraction analysis confirms its isostructural character with previously reported MIL-100(Cr, Fe, Al) solids. Its thermal stability under O2 and N2, up to 523K (250°C), is comparable to that of MIL-100(Fe). Preliminary gas adsorption experiments and in situ IR-spectroscopy after NO exposure reveal that MIL-100(V) combines high sorption capacities and co-ordinatively unsaturated vanadium sites in different oxidation states (+III and +IV). With these properties this material could be a promising candidate for specific sorption or redox catalytic applications. [Copyright &y& Elsevier]

Abstract: The compound MOF-14 (Cu3(BTB)2, BTB=4,4′,4″-benzenetribenzoate) was synthesized by ball milling and characterized by powder X-ray diffraction (XRD). The raw material was activated using an efficient single washing step to ensure a free pore access. Nitrogen adsorption measurements were carried out to determine the specific areas of the samples before and after activation. To interpret the activation process in terms of blocking effects in the micropore channels, NLDFT evaluations (Nonlocal Density Functional Theory) of the MOF-14 nitrogen isotherms were carried out. In connection with the appearance of additional hysteresis loops in the nitrogen isotherms, calculations of the mesopore size distribution were performed using the method of Barret, Joyner, and Halenda (BJH). The results are compared to those of a structurally analogue MOF, namely HKUST-1 (Cu3(BTC)2, BTC=1,3,5-benzenetricarboxylate). This comparison showed notable differences regarding the impact of the activation step on the formation of mesopores and their size distribution. [Copyright &y& Elsevier]

Abstract: The effect of copper ions on the polymerization and the structure of resorcinol–formaldehyde (RF) hydrogels, and on the resulting aerogels, is studied by a range of different techniques. Although the activation energy of the RF reaction in the presence of copper acetate is the same as with sodium carbonate, measurements by dynamic light scattering, small angle X-ray scattering, scanning electron microscopy and nitrogen adsorption reveal appreciable differences in the microscale structure and porosity of aerogels that have been synthesized with or without CuAc, before they are dried supercritically. The presence of copper ions produces a much finer mesh size on the submicron scale and increases the BET surface area of the aerogels to 2000m/g, more than twice as much as those synthesized with sodium carbonate alone. The increase in the volume of wider pores detected by gas adsorption is even more striking. The observed effects can be attributed to the copper acetate. [Copyright &y& Elsevier]

The specific surface area is key for various application fields of porous materials. Its reliable and fast determination is therefore crucial for materials development and product quality management. Surface area assessment is usually based on physical adsorption using the Brunauer-Emmett and Teller (BET) theory. However, the BET method/gas adsorption exhibits a number of limitations and challenges including (i) time consuming sample preparation and measurement time, and (ii) reliable surface areas only possible for non-porous and meso-/macroporous materials to obtain reliable surface areas. In addition, the accuracy of surface area data obtained from adsorption depends on the proper choice of adsorptive/probe. Within this context, this work evaluates in a rigorous way in-depth Small Angle X-ray Scattering (SAXS) as an alternative and complimentary approach for reliable and fast surface area assessment. To our knowledge, this work can be considered the first systematic study where the surface areas from SAXS are compared and validated with true benchmark surface area data. We utilize silica-based nanoparticles as well as a well-defined mesoporous controlled pore glass for systematic SAXS and adsorption studies (argon and nitrogen at 87 K and 77 K, respectively). Owing to the lack of micro- and narrow mesopores of these model materials, the BET method based on argon 87 K adsorption can be applied to determine benchmark surface areas. Indeed, excellent agreement was found between surface areas derived from argon 87 K adsorption and SAXS. In fact, we demonstrate that the determination of specific surface area can be brought with SAXS to a new level, where parameters such as size of the probing adsorptive, its orientation and thus its effective cross-sectional area (when adsorbed on the surface) are no longer affecting the value of the specific surface area determined. Furthermore, SAXS was shown to be significantly faster than gas adsorption. For the silica materials used, the study shows that SAXS does not require degassing and – along with analysis times of only few minutes per sample – provides an accurate and extremely fast, high-throughput approach. This fundamental study can be considered a major step in enabling SAXS for reliable surface area assessment for applications both in nanoporous materials development and quality control, thus boosting SAXS for surface area determination in general, but in particular also for materials, where the usage of gas adsorption is restricted or not possible at all. [Display omitted] • Benchmark BET surface areas based on Ar 87 K adsorption on model silicas. • Excellent agreement of SAXS and Ar 87 K BET surface areas. • SAXS surface area analysis significantly faster than gas adsorption. • SAXS as alternative approach to gas physisorption for reliable surface area assessment. [ABSTRACT FROM AUTHOR]

Abstract: Due to the differences in synthesis procedures used in preparation of metal organic frameworks, surface area and pore volume of the samples usually vary from one laboratory to another. The adsorption characteristics of the frameworks are also affected. In such cases, usually a scaling factor is employed to match isotherms obtained in different laboratories (or those from experiments and simulations). In an attempt to validate the use of a scaling factor, in this work we compare adsorption properties of N2, O2, Ar, CO2, C3H8 and SF6 on Cu-BTC (HKUST-1) framework synthesized using two different procedures. It was observed that Cu-BTC sample with higher surface area and pore volume has greater adsorption capacity for all gases at the two temperatures considered (298.25 and 318.15K). For all gases, the ratio of specific adsorption capacities of the two samples can be broadly classified into two regions. In the low loading region this ratio was about 2.03 with in a 10% uncertainty envelope. However, in the high loading region, it increases to about 2.58. Thus, the scaling factor needed to compare adsorption isotherms of Cu-BTC having different surface areas may not be unique. This value seems to be strongly affected by loading, whereas it is relatively insensitive to the type of gas used, temperature or pressure. [Copyright &y& Elsevier]

Abstract: A cobalt based metal-organic framework [Co2(1,4-bdc)2(dabco)]·4DMF·H2O 1 (1,4-bdc=1,4-benzenedicarboxylate, dabco=1,4-diazabicyclo[2.2.2]octane, DMF= N,N-dimethylformamide) was synthesized using a solvothermal route. The crystals of 1 remain crystalline after solvent molecule removal. A reversible structure change between 1 and the guest-free structure [Co2(1,4-bdc)2(dabco)] 2 was characterized by single crystal X-ray analysis. Compound 1 crystallizes in the space group I4/mcm (No. 140), with a =15.085(2), c =18.906(4)Å, and metal-organic framework 2 in the space group P4/mmm (No. 123), with a =10.963(4), c =9.466(3)Å. The compound 2 has a specific micropore volume of 0.82cm3 g−1, a hydrogen storage capacity of 2.27wt.% at −196°C and 1bar, and an excess methane adsorption of 14.0wt.% at 30°C and 75bar. [Copyright &y& Elsevier]

Abstract: In this study, we synthesized four new lanthanide coordination polymers: CKMOF-1 [Ce2(CO3)2(C2O4)(H2O)2]·2H2O, CKMOF-2 [Ln2(C4H4O4)2(C2O4)(H2O)4]·4H2O (Ln=Ce, Nd), and CKMOF-3 [Na2Nd2(C4H4O4)(C2O4)3]·4H2O. For CKMOF-1, the cerium ions are extended with carbonate ligands to form networks possessing 2D inorganic skeletons, which are pillared by oxalate ligands to yield open channels featuring water molecules distributed within. For CKMOF-2, succinate ligands replace the carbonate ligands in the networks and separate 2D inorganic skeleton into 1D inorganic chains. Similarly, oxalate ligands act as pillars to generate an open framework with channels existing along multiple directions. For CKMOF-3, dimeric neodymium units are assembled with in-planar oxalate ligands to form honeycomb-like networks, which are pillared by out-of-plane oxalate ligands to generate an open framework with sodium counteractions distributed around the channel walls. The dehydrated solid [Ce2(CO3)2(C2O4)(H2O)2] retained the crystallinity of its original CKMOF-1 phase. The dehydrated solid [Nd(C4H4O4)2(C2O4)] maintained the framework porosity of CKMOF-2, but lacked long-range ordering; a reversible hydration process converted this distorted phase back to the highly crystalline state in CKMOF-2. Decreases in the values of χ MT with decreasing temperature indicate that the main contributions from spin–orbital couplings were accompanied by weak magnetic interactions. [Copyright &y& Elsevier]

Abstract: A new organic–inorganic hybrid mesoporous zirconium oxophenylphosphate (ZPP-1) has been synthesized hydrothermally at 443K by using phenylphosphonic acid (PPA) as phosphorus source in absence of any structure directing agent. Powder XRD, TEM, FE SEM, N2 sorption, CHN and ICP-AES chemical analyses, 13C CP/MAS and 31P MAS NMR, UV–visible and FT IR spectroscopic tools and thermal analysis were employed to characterize this novel material. XRD, N2 sorption and TEM image analysis suggested the existence of multi-lamellar structure of the pore wall with large micropores and mesopores having peak maximums of ca. 1.5 and 5.0–6.0nm, respectively in this ZPP-1 material. Interestingly, this hybrid material showed very high thermal stability together with retention of nanostructure and phenyl group when heated upto 723K. ZPP-1 showed fairly high H2 adsorption capacity under atmospheric pressure at 77K. Possible templating role played by the framework phenyl groups has been discussed. [Copyright &y& Elsevier]

Abstract: Ion exchange of H–SAPO-34 zeolite membranes with Li+, Na+, K+, , and Cu2+ cations in non-aqueous solutions increased CO2/CH4 ideal and separation selectivities up to 60%, but increased H2/CH4 ideal and separation selectivities less than 18%. Ion exchange decreased permeances, and the decrease was larger for large cations, apparently due to steric hindrance. Exchange did not degrade SAPO-34 crystals or membranes, but changed adsorption properties for some ions. [Copyright &y& Elsevier]

Abstract: Hyperpolarized 129Xe NMR spectroscopy is used to investigate the interaction of xenon with four different zinc metal–organic frameworks, IRMOF-1, -7, -8, and -10. Each of the frameworks has a cubic cage of varying size, depending on the organic linker molecule. The 129Xe NMR chemical shifts are influenced by both the cage dimensions and the distribution of xenon within the framework. NMR spectra acquired at low temperature suggest that high xenon loadings can be achieved using the continuous-flow hyperpolarized 129Xe NMR experiment. Information about the adsorption energy is inferred from the behaviour of the xenon chemical shifts as a function of temperature and analyzed for IRMOF-10. The rate at which xenon diffuses through the IRMOF is probed using a signal recovery NMR experiment. [Copyright &y& Elsevier]

Abstract: A new technique to produce highly porous SiO2-aerogels inverse opals in supercritical carbon dioxide (scCO2) is being developed at our laboratory. Polystyrene latex particles decorated with methacrylic acid or a mixture of methacrylic and itaconic acid groups are organized in three-dimensional 3D-latex arrays and used as templates. The polymeric template is reacted with tetraethylorthosilicate (TEOS) or tetramethylorthosilicate (TMOS) dissolved in scCO2 at 40°C and 85bar. The reaction is catalysed by organic acids attached to the latex particle surface. SEM and TEM images show that, upon calcination of the template, highly porous materials replicating the structure of the original template are obtained. N2-adsorption isotherms reveal the presence of a large porosity located in the macropore wall. In all the cases, the maxima in the pore size distribution appear in the mesopore range. In this paper we investigate ways of controlling the porosity of the material by changing the precursors, the catalyst and/or its concentration. SEM, TEM and N2-adsorption data show that, at the reaction conditions, reactivity of TEOS and TMOS on the templates is similar, yielding materials of comparable surface area. In the same way, the porosity of the aerogels obtained with templates impregnated using benzosulfonic (BSA) acid and p-toluene sulfonic acid is the same. Lower yields were obtained using monochloroacetic acid. The effect of the catalyst concentration is more important; as the concentration of BSA in the template increases, lower values are obtained for the maximum in the pore size distribution. [Copyright &y& Elsevier]

Abstract: In the present study, adsorption equilibrium and kinetic separation potential of β-zeolite is investigated for N2, O2, CO2 and CH4 gases by using concentration pulse chromatography. Adsorption equilibrium and kinetic parameters have been studied. Henry’s Law constants, heat of adsorption values, micro-pore diffusion coefficients and adsorption activation energies are determined experimentally. The three different mass transfer mechanisms, that have to take place for adsorption to occur, are discussed. From the equilibrium and kinetic data, the equilibrium and kinetic selectivities are determined for the separation of the gases studied. With β-zeolite, carbon dioxide has the highest adsorption Henry’s Law constant at all the temperatures studied, followed by methane, nitrogen and oxygen. Carbon dioxide separation from oxygen, nitrogen and methane has good equilibrium separation factors. This factor is not very high for methane/nitrogen and methane/oxygen systems and is the lowest for nitrogen/oxygen system. Micro-pore diffusion is the dominant mass transfer mechanism for all the systems studied, except CH4, with β-zeolite. The kinetic separation factors are very small at high temperatures for all the systems studied. Nitrogen/carbon dioxide and oxygen/carbon dioxide can be separated in kinetic processes with reasonable separation factors at low temperatures. Both equilibrium and kinetic separation factors decrease as column temperature increases. Considering all the observations from this study, it was concluded that β-zeolite is a good candidate for applications in flue gas separations, as well as natural gas and landfill gas purifications. [Copyright &y& Elsevier]

Abstract: The geometric and structural properties of pore surfaces of microporous carbon specimens were investigated using high resolution transmission electron microscopy (HRTEM) and nitrogen gas adsorption method based upon the fractal theory. The carbon powder specimens with various pore structures were prepared by reactivation of commercially as-activated carbon powder at 1273K in an atmosphere of a CO2/CO gas mixture for different activation times. The surface fractal dimensions d F,surf of the carbon specimens were evaluated from the image analysis of the HRTEM images using perimeter–area method. In addition, the pore fractal dimensions d F,pore of the carbon specimens were determined from the analyses of nitrogen gas adsorption isotherms using non-linear fitting method based upon Dubinin–Astakhov adsorption theory in consideration of fractal pore size distribution. From the results of the image analyses of the HRTEM images, it was found that the surface fractal dimension d F,surf of the carbon specimens decreased in value with increasing degree of burn-off, which is ascribed to the more agglomeration of micropores by collapsing the pore walls between the pores. Moreover, from the quantitative coincidence of the nitrogen gas adsorption isotherms experimentally obtained with those theoretically calculated, it is suggested that the pore fractal dimension d F,pore of the carbon specimens is closely related to their porosity, i.e. as the pore fractal dimension d F,pore decreases, the relative volume fraction of the pores with larger size increases as well. [Copyright &y& Elsevier]

The adsorptions of CO, CO2 and SO2 gases by two bentonitic clay minerals from Patagonia, Argentina, in their natural state and after acid treatments, were analyzed. The clay minerals (bulk and <2 μm size fraction) were modified with 3.0 and 6.0 N HCl solutions at boiling temperature during 3 h. The samples were characterized by chemical analysis, X-ray diffraction and by N2 adsorption–desorption isotherms. Equilibrium adsorption of the gas was measured at 25 °C and 1 kg/cm2. Gas adsorptions by bentonitic clay minerals increased after acid treatments and the values were analyzed as a function of structural and textural changes. The retention values of the SO2 (0.636–1.232 mmol/g) by clay minerals were higher than CO2 (0.218–0.516 mmol/g) and CO (0.075–0.119 mmol/g). A high smectitic component in the original clay mineral, an increase in BET surface and micropore volume and an increase of the Si/(Al+Fe+Mg+Ti) ratio of the materials after acid treatments influenced to get a larger retention of the CO2 and SO2 gases. [Copyright &y& Elsevier]

To achieve the selectivity of luminescent sensing and gas separation, an unprecedented nanocages based 3D amino-functionalized MOF, {(Me 2 NH 2)[Zn(NH 2 -TCB)]} n (ZnMOF) was constructed through ligand pre-design strategy. ZnMOF contains a unique 1D triple [Zn(COO)] n helix chain SBU and forms 7.89 × 11.72 × 14.79 Å3 nanocages with the porosity up to 42.9%. Benefit from the outstanding thermal and chemical stabilities, the ZnMOF demonstrates considerable adsorption selectivity for CO 2 /CH 4 and highly sensitive detectability to Cr(VI) anions and nitroimidazole/nitrofuran antibiotics in water. In addition, the high selective adsorption and sensing mechanisms were also explored. Therefore, ZnMOF is a multifunctional material in the efficient gas adsorption and separation, and the detection of Cr(VI) anions and nitroimidazole/nitrofuran antibiotics. An unprecedented nanocages based amino-functionalized ZnMOF shows considerable selectivity in gas adsorption and luminescent sensing for Cr(VI) anions and antibiotics in aqueous media. [Display omitted] • An unprecedented amino-functionalized nanocages based ZnMOF was designed with the porosity is 42.9 %. • ZnMOF shows high uptake for N 2 and H 2 and considerable adsorption selectivity for CO 2 /CH 4. • ZnMOF were implemented as dual-responsive luminescent sensors to detect Cr(VI) anions, and antibiotics in water, simultaneously. • The mechanism of selective adsorption and luminescence sensing were investigated. [ABSTRACT FROM AUTHOR]

A magnesium-based metal-organic framework (MOF), Mg-MOF-74, has been denoted as a landmark for CO 2 capture due to its highly porous structure and strong metal adsorptive sites. However, the gas uptake would be improved if particle texture could favor diffusion into the micropores and accessibility to the adsorption sites. For that reason, multi-wall carbon nanotubes (CNT) or monolayer graphene oxide (GO) was introduced into the MOF material at 0.3 wt% via in-situ synthesis method as an attempt to improve gas adsorption capacities. Mg-MOF-74, Mg-MOF-74@CNT and Mg-MOF-74@GO were synthesized under solvothermal reaction and characterized by PXRD, FTIR, FESEM, TGA and N 2 @77 K and CO 2 @298 K adsorption/desorption analysis. The morphology of the Mg-MOF-74 composites showed that the particles were composed of agglomerated crystallites of which the crystal structure was well-preserved with the adjunction of carbon doping agents. The BET specific surface area and the micropore volume of the Mg-MOF-74 pristine material respectively attained 1370 m2/g and 0,4 cm3/g whilst these values were increased up to 1660–1720 m2/g and ̴ 0.49 cm3/g for carbon composites. These variations were attributed to better activation of carbon-MOF composites thanks to more regular arrangement of the crystallites composing the agglomerates, facilitating the evaporation of the organic solvent during the thermal treatment applied in the last stage of the synthesis. The introduction of a small fraction of CNT and GO in the reactant mixture also improves the crystallization process, leading to average larger particle sizes. Consequently, the uptake of CO 2 at 1 bar and 25 °C was shown to be improved by 18 mol% and 23 mol% for Mg-MOF-74@CNT and Mg-MOF-74@GO, respectively, compared with the pristine Mg-MOF-74. This current work demonstrates that by doping Mg-MOF-74 synthesis with carbonaceous agents, although at very low concentration levels, both morphological and textural properties are modified leading to larger gas adsorption capacities. [Display omitted] • Graphene oxide and carbon nanotubes were used as doping agents for synthesis of GO and CNT- Mg-MOF-74 composites. • GO and CNT doping induced more regular arrangement of the crystallites and average larger particle sizes of the composites. • Thanks to larger specific surface areas and micropore volumes, composites exhibit higher CO2 adsorption capacities. [ABSTRACT FROM AUTHOR]

Polymer functionalization of ordered mesoporous silicas (OMS) offer wide applications owing to their synergy properties. In this study, a new approach for polymer functionalization of OMS is demonstrated by the co-condensation of silica precursor and a functional polymer bearing triethoxysilane end-group in the presence of a tailored poly (ethylene oxide)- b -polystyrene (PEO- b -PS) amphiphilic copolymer used as pore template. The novelty of this strategy resides in the co-micellization of PEO- b -PS and functional polymer that enables the incorporation of the latter into the mesoporous silica. By changing the nature of the functional polymer, as well as their loading concentration and process conditions, different ordered polymer-mesoporous silicas containing aryl, nitro or amide groups and high polymer content, up to 38 wt% were synthesized. These materials exhibit high specific surface area (488 m2 g−1) and large pores (8 nm) with acceptable CO 2 adsorption capacity and selectivity towards CH 4 and N 2. [Display omitted] • Co-condensation of silica precursor and triethoxysilane-end capped functional polymer. • Co-micellization of amphiphilic block copolymer template and functional polymer. • Ease modulation of polymer content and mesostructure of mesoporous silica. • CO 2 adsorption performance of nitro-based polymer functionalized mesoporous silica. [ABSTRACT FROM AUTHOR]