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AbstractIn this report we present a simple synthesis of a nickel-based metal organic framework (MOF-Ni) at the room temperature using a solution of dimethylformamide (DMF), ethanol and distilled water. The MOF-Ni synthesized in various solvents displayed numerous different properties and advantages over other materials including easy synthesis procedure, good crystallinity, rigidity, and robust chemical stability. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and thermal gravimetric analysis (TGA) were employed to analyze the as-synthesized MOF-Ni. The as-obtained MOF-Ni was used to investigate its adsorption kinetics of red telon dye (RTL) molecules. The effects of time (30–270 min), initial RTL concentration (20–300 mg/L), adsorbent dose (2–50 mg), solution pH (2–12), and temperature (10–80 °C) were investigated. The pseudo-first order rate equation was able to provide the best description of the adsorption kinetics data in the studied time scale. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms, and the isotherm constants were also determined. Dye adsorption turned out to strongly depend on pH, and a low pH was found to increase the amount of adsorbed dyestuff. Compared with other samples, MOF-Ni synthesized in (DMF ​+ ​C2H5OH ​+ ​H2O) had a significantly enhanced adsorption ability for RTL dye. The MOF-Ni high adsorption capacity for RTL dye was attributed to the electrostatic attraction/repulsion phenomena. Moreover, MOF-Ni showed an improved stability at 370, 417, and 423 °C temperatures. The results obtained through our experiments suggested that our porous MOF-Ni microstructures synthesized in DMF ​+ ​C2H5OH ​+ ​H2O have potential applications for treating wastewaters containing RTL dyes. [ABSTRACT FROM AUTHOR]

Propylene (C3H6) is a crucial olefin raw material used in the production of polypropylene, which is the world's second-most produced synthetic plastic. Separating propylene from propane (C3H8) is an important and significant challenge for industry due to the similar molecular sizes and physical properties of these gases. At present, the usual method for this separation is energy-intensive cryogenic distillation, which has low efficiency and high energy consumption. Therefore, an energy-efficient alternative way is in an urgent demand. Metal-organic frameworks (MOFs) are promising candidates for propylene/propane separation, thanks to the well-defined, designable, modifiable, and flexible structures. This review provides a summary of a recent development of MOFs that are able to discriminate between propylene and propane. The key factors that determine the separation performance of MOFs, primarily from the perspectives of pore size, presence of open metal sites (OMS) and MOFs membranes are summarized. Besides, the challenges that must be addressed for the further development of separations utilizing MOFs are also discussed. [ABSTRACT FROM AUTHOR]

Intensive urbanization and industrialization has led to increasing water pollution by heavy metals, adversely affecting human health and the environment. Among the different technologies available for heavy metals removal from water, adsorption is regarded as the most effective approach. Nanomaterials, especially magnetic nanoparticles, have emerged as promising tools for heavy metals removal because of their unique properties. One of the main drawbacks with magnetic nanoparticles is their tendency to form aggregates in solution, decreasing their efficacy and limiting their applications in water treatment. In order to stabilize magnetic nanoparticles, researchers have therefore begun modifying their surfaces with a variety of support media. In addition to carbon-based materials, natural and synthetic polymers and other molecules, metal organic frameworks and layered double hydroxides have all been employed as carriers in novel magnetic nanocomposites. This review summarizes the most recent developments in this field, focussing on the potential application of magnetic nanocomposites as adsorbents for removing heavy metals from water. Critical gaps in the current literature are also identified, as much work is still required before magnetic nanocomposites may be readily applied in real world applications, including scale up of production and subsequent pilot investigations of water treatment in dynamic flow conditions. Heavy metal contamination of water resources is a serious global problem Much work has focused on developing magnetic nanocomposites as heavy metal adsorbents This work summarizes recent research efforts in this field Magnetic nanocomposites show great promise for heavy metal removal applications Scale-up and pilot studies are needed to bring their realization closer to fruition [ABSTRACT FROM AUTHOR]

Extensive use of imidacloprid in pest control and its unfavourable removal efficiency has resulted contamination of aquatic environments. Herein, 4,4ʹ-methylenedianiline nano-polymer (MDANP) as organic linkers and Cu, Fe, and Al as metal sources were used to synthesise several metal-organic frameworks (MOFs) nanomaterials. Three MOFs (MDANP/Cu, MDANP/Fe, and MDANP/Al) were synthesised by the electrochemical polymerisation method and used as a nano-adsorbent to remove imidacloprid from the aqueous environment. Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), transient electron microscopy (TEM), and Field-scattering scanning electron microscopy (FE-SEM) techniques were used to analyse physicochemical characteristics of produced MDANP and MOFs. Kinetic data have been fitted with pseudo-second-order models; according to the obtained correlation coefficients (R2 = 0.9993). Adsorption isotherm models suggested that except imidacloprid adsorption on MDANP, which was best explained by the Freundlich model (R2 = 0.9018), pesticide adsorption from MOFs was well explained by the Langmuir model (R2 = 0.9473). The removal efficiency of imidacloprid onto MDANP and MOFs decreased from 65.28% to 40.25% and from 61.56% to 36.89%, respectively, as the initial concentration of imidacloprid increased from 25 to 400 mg/L. The results showed that the highest adsorption of imidacloprid happens within 120 min for 150 mg of adsorbent. Under optimum conditions, a maximum adsorption capacity of 97.4 mg/g occurred. Thus, MDANP and MOFs have medium potential for environmental implications and can be exploited as nano-adsorbents of imidacloprid pesticides in aquatic environments. [ABSTRACT FROM AUTHOR]

Contamination of water with heavy metals being discharged from several industrial activities has been gaining serious concern from quite a long time. Lead (Pb) is one of the highly toxic and harmful heavy metal that is present in high concentration in contaminated water. Several adsorption techniques have been investigated both using chemical and biological methods. The adsorption of Pb (II) ions was found to be affected by solution pH, contact time, adsorbent dosage, initial metal ion concentration, and temperature. This study compares different chemical and biological methods for lead ion removal based on their properties and adsorption capacity. It is found that the chemical adsorption is quite efficient and chemical adsorbents have a higher removal percentage and adsorption capacity than the biological methods. Among the chemical methods, metal organic frameworks (MOFs) exhibit the highest metal adsorption capacity of 909 mg.g−1 due to their large surface area and high porosity. The ongoing and future research aims at minimising the contamination of wastewater from heavy metals and metal organic frameworks contain the potential to build the gap. [ABSTRACT FROM AUTHOR]

Porous metal organic framework (TMU-10) has been fabricated via solvothermal method. The TMU-10 was further post synthetically modified to TMU-10@GO hybrids with graphene oxide (GO). The prepared TMU-10@GO hybrids were used as an effective adsorbent to removal of phenol in environmental water samples. The TMU-10@GO hybrids adsorbent was characterised by X-ray diffraction (XRD), infrared Fourier transform spectrometer (FTIR), and scanning electron microscopy (SEM), EDX. The influence of different parameters including pH, amount of adsorbent, salt additive and contact times were studied. Using the phenol experiment to evaluate the adsorption performance, TMU-10@GO hybrids displayed better adsorption capacity towards phenol, compared with TMU-10.The results showed that the phenol adsorption obeyed the pseudo-second-order kinetic and the Langmuir isotherm with the experimental adsorption data. The maximum adsorption capacity of phenol with TMU-10@GO adsorbent was 212.76 mgg-1.TMU-10@GO hybrids was suggested as a promising adsorbent for the removal of phenol from water, based on the remarkably high adsorption capacity and rapid adsorption. [ABSTRACT FROM AUTHOR]

Mismanagement of plastic waste results in its ubiquitous presence in the environment. Despite being durable and persistent materials, plastics are reduced by weathering phenomena into debris with a particle size down to nanometers. The fate and ecotoxicological effects of these solid micropollutants are not fully understood yet, but they are raising increasing concerns for the environment and people's health. Even if different current technologies have the potential to remove plastic particles, the efficiency of these processes is modest, especially for nanoparticles. Metal-organic frameworks (MOFs) are crystalline nano-porous materials with unique properties, have unique properties, such as strong coordination bonds, large and robustus porous structures, high accessible surface areas and adsorption capacity, which make them suitable adsorbent materials for micropollutants. This review examines the preliminary results reported in literature indicating that MOFs are promising adsorbents for the removal of plastic particles from water, especially when MOFs are integrated in porous composite materials or membranes, where they are able to assure high removal efficiency, superior water flux and antifouling properties, even in the presence of other dissolved co-pollutants. Moreover, a recent trend for the alternative preparation of MOFs starting from plastic waste, especially polyethylene terephthalate, as a sustainable source of organic linkers is also reviewed, as it represents a promising route for mitigating the impact of the costs deriving from the widescale MOFs production and application. This connubial between MOFs and plastic has the potential to contribute at implementing a more effective waste management and the circular economy principles in the polymer life cycle. [ABSTRACT FROM AUTHOR]

Pillar-layered metal-organic frameworks (PL-MOFs) are advanced crystalline porous substances built using metal ions, oxygen- and nitrogen-donor linkers. The pillar-layered strategy emerged as a very effective way to incorporate the Schiff base functionalities into pore cages of MOFs by using N-donor Schiff base pillar ligands. The Schiff base functionalities provide active sites for enhanced performance in sensing, catalysis, adsorption, extraction, and gas separation areas. Although the PL-MOFs have gained remarkable advances in the last few decades, Schiff base PL-MOFs have been reviewed to a lesser extent up to this point. In this way, a review summing up their performance is profoundly expected. This review covered the recent developments connected with Schiff base PL-MOFs, including synthesis and applicability in various potential fields. It also included the challenges and forthcoming pathways for fulfilling the research and development needs of Schiff base PL-MOFs. [ABSTRACT FROM AUTHOR]

UiO-66 Metal-Organic framework (MOF) has been highlighted since its synthesis for its stability and many potential applications. Lead (II) and mercury (II) water remediation are among them. In the present work, we used density functional theory calculations, cluster models, and density analysis tools to study the lead and mercury adsorption mechanism of modified UiO-66. We have included the SH (thiol), NCS (isothiocyanate), NMeTU (N-methylthiourea) and DMTD (2,5-dimercapto-1,3,4-thiadiazole) linker groups. The results show a clear trend in capturing both metals: DMTD > NMeTU > SH > NCS. For mercury adsorption, little energy difference for DMTD (bidentate) and NMeTU (monodentate) is found, while for lead, this gap is greater. Inspection of charges and descriptors as softness in conceptual DFT showed the relevance of charge transfer in mercury capture by NMeTU, making this interaction almost as strong as the bidentate fashion through sulfur and nitrogen atoms in DMTD. Lead capture shows charge transfers of lesser magnitude, so the preferred interaction fashion is bidentate. Electronic density difference maps show qualitative visualization of results and are consistent with interaction energies. Through non-covalent interaction (NCI) analysis, it was possible to conclude that at DMTD, the interaction for both metals was stronger with nitrogen atom than sulfur. [ABSTRACT FROM AUTHOR]

Water is one of essential resources of modern society. Employing cost-effective technologies to treat water and wastewater is of vital importance for household uses, industries and the environment. Water-stable metal-organic frameworks (MOFs) have emerged as promising innovative materials for water treatment, due to their versatility and properties such as large internal surface area, designable pore sizes, and chemical functionalities. In highly porous MOFs, metal center(s)/cluster(s) and organic ligands are linked with coordination bonds. This review paper presents the most recent developments in the industrial-scale synthesis of MOFs and applications in water purification. MOFs can be fabricated by several approaches; the microwave assisted continuous flow synthesis technologies can lead to higher production yields. The fabricated MOFs are then purified by the organic solvent and/or the solid separation, and activated by a few technologies (e.g., supercritical C O 2 ). Process safety in production, reactors design, and process optimization are important in production. The shaping techniques for MOFs on supporting materials via surface grafting/coating or embedment can be used to fabricate the MOFs-based materials with the better stability suitable for industrial applications. MOFs demonstrate much better performances than the commercially available materials in adsorption, filtration, sensing, and catalysis. Toxicity from MOFs is mainly due to the chemicals involved in the production and nano-size effects on human cells. Mitigation strategies like environmental-friendly processes for fabrication of MOFs and shaping using polymer are suggested. Various advantages from MOFs make them suitable for water treatment in the near future. [ABSTRACT FROM AUTHOR]

Green application of a high-nitrogen, zeolite-like, porous metal–organic framework, IFMC-1 (Institute of Functional Material Chemistry), is reported for dye pollutant removal and wastewater treatment. The IFMC-1 contained a high-nitrogen-content ligand without an NH2 group (H3dttz), dimethylacetamide, and Zn ion. The synthesis of H3dttz from diaminomaleonitrile was initiated after closure of the triazole ring and formation of 4,5-dicyano-2H-1,2,3-triazole as an intermediate material; thus, two tetrazole rings were obtained in a 1,3-dipolar cycloadditionn. Only four nitrogens of the IFMC-1 ligand coordinate with zinc, and 63.6% of the nitrogens are free. The IFMC-1-based tetrazole without an NH2 group was investigated for removal of methylene blue (MB) and basic red 46 (BR-46) pollutants. The results indicated that the IFMC-1 adsorbent effectively removed the MB and BR-46 dyes from solution. The contaminant adsorption capacity of IFMC-1 for MB and BR-46 was 293.9 and 135.2 mg g–1, respectively. Investigation of isotherm and kinetic data of dye removal using the synthesized absorbent indicated that it follows the Langmuir isotherm and pseudo-second-order kinetics. [ABSTRACT FROM AUTHOR]

Laccase, as an important biocatalyst, has aroused wide public interests in the field of environment and catalysis. However, the application of laccase in large-scale is still limited due to its high solubility and poor stability. In order to improve the reusability of laccase, immobilization with functional materials has attracted increasing attention. Metal-organic frameworks (MOFs) stand out as a promising carrier for its high adsorption capacity and flexible structure. The present paper reviews the current status and remaining challenges in the immobilization of laccase with MOFs. Furthermore, three methods are proposed to further improve the immobilization of laccase with MOFs, including co-immobilization of laccase and mediator, co-immobilization of laccase and other enzymes, and coupling of biocatalysis with photochemical reactions. This work, as the first review article on the immobilization of laccase with MOFs, will provide a navigation map for the subsequent selection and design of MOFs for more targeted immobilization of laccase. [ABSTRACT FROM AUTHOR]

Wastewater remediation technologies are rapidly evolving to meet the increasing water demand. The need to develop efficient, low-cost, and simplistic strategies has motivated researchers to explore newer fields of material science. Owing to high thermal stability, porosity, and accessible functionalities, metal-organic frameworks (MOFs) are finding numerous applications in the domain of wastewater treatment and resource recovery. The application-oriented development of MOFs has been accepted as a novel approach for the removal and recovery of metals from waste solutions. The desired properties in MOFs could be achieved by adopting suitable synthesis or post-synthesis functionalization strategies. Here, we have reviewed differently functionalized MOFs and their application in the removal of metals from waste solutions. We have also discussed the application of MOFs in the pre-concentration and recovery of actinides from seawater. Conclusions regarding the future scope of employing MOFs in the domain of environmental remediation have been included. [ABSTRACT FROM AUTHOR]

This paper describes the synthesis and characterization of Zn2+ decorated (adipic and terephthalic acid as linkers) piperazine-based metal-organic framework (P-MOFs) and their extraction behavior toward the Chicago sky blue (CSB) dye. The formation of Zn2+-decorated P-MOFs was confirmed by FT-IR spectroscopy, energy-dispersive spectroscopy, X-ray diffraction, BET surface area analysis and TGA. Adsorption behavior of the synthesized P-MOFs was explored through solid-phase adsorption (batch method) prior to UV-Vis spectrophotometric determination. Adsorption parameters, including adsorbent dosage, pH of solution, dye concentration, and time, were optimized. Excellent percentage removal of 94% and 95% for AP-Zn-MOF and TP-Zn-MOF, respectively, was achieved at pH 7.5. Kinetics studies indicated that the synthesized adsorbents AP-Zn-MOF and TP-Zn-MOF followed the pseudo-second-order rate model with R2 value 0.9989. The Freundlich isotherm with high R2 value as compared to Langmuir isotherm indicated that CSB adsorption for the synthesized MOFs follows multilayer adsorption. [ABSTRACT FROM AUTHOR]

A series of metal organic frameworks with amino group and excellent hydrostability were designed and fabricated by means of regulating organic ligands, which were characterized and used to enrich oleuropein from aqueous solution. The results showed that the specific surface area and pore structure could be modulated and overmuch amino group would be unfavorable for the adsorption efficiency for oleuropein. Hydrogen bonding, sieving effect hydrophobic interaction, and π-π were involved in the adsorption process. The excellent adsorption efficiency and regeneration make the present materials highly promising useful in practical application to enrich oleuropein from aqueous solution. [ABSTRACT FROM AUTHOR]

Herein we reported a new Zn2+ metal–organic framework (MOF) (based on adipic acid as a linker and benzylimidazole as a ligand) (ABim-Zn-MOF) adsorbent material for the efficient removal of cationic (methylene blue, MB) and anionic dyes (Chicago sky blue, CSB. The newly synthesized adsorbent exhibits excellent adsorption capacity calculated to be 144.26 and 174.64 mg g−1 for CSB and MB, respectively. The kinetic model analysis indicated that the synthesized MOF followed the pseudo-second-order rate model with calculated R2 value of 0.991 and 0.993 for CSB and MB, respectively. The adsorbent also exhibited excellent application in environmental wastewater treatment with 98% recovery for the mixture of dyes in real water sample. [ABSTRACT FROM AUTHOR]

Separation of methane (CH4) from other gases is of importance to reducing greenhouse gas emissions. In particular, the development and discovery of efficient adsorbents under pressure swing adsorption (PSA) conditions is a focus of many research papers. We evaluated the potential of CH4/N2 separation performance using four adsorbents, including zirconium-based metal organic frameworks (NU-1000, UiO-66, and UiO-67) and a conventional adsorbent, Zeolite-13X. Among them, NU-1000 presented high CH4/N2 selectivity (2.8) at 15 bar through ideal adsorbed solution theory because it has micro- and mesopores coupled with large surface area and a polar hydroxyl group along the pore surface. NU-1000 has a large CH4 working capacity (4.79) under PSA processes. These results demonstrated that NU-1000 is a competitive adsorbent in PSA processes for CH4/N2 separation. [ABSTRACT FROM AUTHOR]

In this article, we present a high-throughput computational screening of 12 , 351 real metal–organic framework (MOF) structures to identify the best candidate material for the separation of propane/propene mixture. We assessed the performances of the MOFs by calculating various metrics such as adsorption selectivity, working capacity, regenerability and adsorbent performance score (APS). All most all of these MOFs are selective to propane over propene. We looked at various structures–property correlations that revealed some useful insights and ways of tuning the structural properties of the MOFs to yield high performance. The MOFs were ranked on the basis of APS. MOF RUFPUF was found to be the best performing MOF with a highest APS value of 15.62 mol/kg and R % > 80. We also screened out few potential stable MOFs containing tetravalent metal cations such as Zr4+, HF4+ and Ti4+. MOF BOLZIN (NU-1100) was found to be the best performing stable MOF with APS 10.32 mol/kg and R % = 89.73. [ABSTRACT FROM AUTHOR]

In this study, functionalized MIL-101(Cr) with amine group (ED-MIL-101(Cr)) was Synthesized. Using grafted MOF, adsorption experiments of Cu(II) and Cd(II) ions in single and binary solutions were performed. The adsorption results were fitted well by the Langmuir and extended Freundlich models for single ion and binary ion solutions, respectively. Data revealed that ED-MIL-101(Cr) possess maximum adsorption capacities (mg/g) of 69.9 and 63.15 for Cu(II) and Cd(II), respectively,with affinity order Cu(II) ˃ Cd(II) in binary ion solution. The kinetic data was well described by the pseudo-second-order model. The amino-functionalized MIL-101(Cr) can be a promising candidate for metal ion removal from the aqueous environment. [ABSTRACT FROM AUTHOR]

Heavy metal contamination and its detrimental effects on human health and environment have been a worldwide concern. Over the years, various technologies have been adapted to tackle this problem. Adsorption is still considered to be one of the most feasible and cost-effective methods for treating wastewater contaminated with heavy metals. Adsorbents such as activated carbon, clay, zeolites and silica have been studied extensively in the past. Modification of these conventional adsorbents and the synthesis of nonconventional adsorbents such as nanocomposites and metal organic frameworks (MOF's) have been the main focus of study in recent times. This review article attempts to present a detailed account of various adsorbents and their removal efficiencies for the treatment of wastewater contaminated with lead(II), zinc(II) and cobalt(II) in the current decade. Influence of various parameters, adsorption isotherms and kinetics best described for their removal have also been reviewed in detail. It is observed that most of the adsorbents followed pseudo second order kinetics suggestive of a chemisorption process. After conducting a thorough review of more than 120 recently published papers, it can be inferred that nanomaterials and nanocomposites have shown excellent adsorption capacity for removal of these heavy metals. [ABSTRACT FROM AUTHOR]

Cadmium as a highly toxic metal is released into the environment through paper production, metal processing, phosphate fertilizers, insecticides, and treatment of wastewater. Cadmium also inhibits the body activities and is very toxic for kidney and other organisms. In the current study, zinc-based metal–organic framework, zeolitic imidazolate framework (ZIF)-8, was synthesized and modified by dimethylethylenediamine (ZIF-8-mmen) for the removal of cadmium. To optimize the experiments, response surface methodology was applied with three variables including pH, adsorbent dosage, and contact time using central composite design. The optimum conditions for pH, dosage, and time were 2, 0.1 g, and 89 min, respectively, with removal efficiency of 85.38%. The Langmuir isotherm (qm = 1000 mg/g) indicates the monolayer adsorption. The kinetic studies reveal that the Lagergren model was predominant and cadmium was not chemisorbed. Thermodynamic parameters show spontaneous, endothermic, and physisorption processes. [ABSTRACT FROM AUTHOR]

High-energy demands due to globalization have led to the proliferation of nuclear technology as an alternative greener energy source to meet these demands. With this proliferation comes the release of large amounts of radionuclides into the environment. Zeolitic imidazolate frameworks (ZIFs) with tunable porous structures and numerous active sites have proved to be excellent at removing these radionuclides from various environmental media. These active sites due to the presence of functional groups allow for favorable sorptive interactions between ZIF-based materials and radionuclides. With their excellent chemical stability in refluxing organic and aqueous media, ZIFs hold a special place among metal-organic framework materials with respect to capturing various types of radionuclides. Moreover, other favorable characteristics such as high thermal stability, high framework porosities (ZIF-8 surface area as high as 1970 m2 g−1) and abundant functional groups, make them suitable for capturing radionuclides. In this review, recent advances in the sequestration of radionuclides with ZIFs and their derived materials (composites, derivatives) are highlighted. The challenges and prospects in this fast-growing branch of coordination chemistry are briefly discussed. This work, being the first of its kind to the best of our knowledge will serve as grounding for the future development of ZIF-based materials for radionuclide removal from the environment. [ABSTRACT FROM AUTHOR]

The study aims to use waste plastic PET bottles to recover terephthalic acid for preparing copper-1,4-benzenedicarboxylate, which was then utilized as an adsorbent for removal of methylene blue (MB) from aqueous solutions after carefully characterizing by XRD, FTIR, TGA, SEM, and EDX. The optimum conditions were established as pH = 6, 25°C, adsorbent dose of 1 g L−1, contact time of 20 min, and agitation speed of 150 rpm. The adsorption process was spontaneous, exothermic, fitting well to Langmuir isotherm model with the maximum adsorption capacity of 41.01 mg g−1 and more suitable to be described by the pseudo first-order kinetic model. It was indicated that the physical adsorption plays a leading role in the adsorption process. The recycling study was also conducted to confirm the long-term use of the synthesized adsorbent. [ABSTRACT FROM AUTHOR]

An unusual metal-organic framework, {H[Ag(I)L][Mo(VI)4O13]}n (1) (L=(4-((1H-1,2,4-triazol-1-yl)methyl)phenyl)methanol)), has been obtained under ionothermal conditions. According to the single-crystal X-ray diffraction analysis, 1 is a new 3-D framework based on β-[Mo8O26]4− type polymolybdate anions with two kinds of channels (A and B) along the b-axes and c-axes in the framework. The neighboring inorganic Mo8-Ag chains are linked by the organic ligands through the Ag centers resulting in 2-D layers. These adjacent 2-D layers extend into a 3-D framework through Ag1 nodes and β-[Mo8O26]4− anions, respectively, resulting in a topological symbol (64 · 82)2(64 · 82). In addition, the gas adsorption, proton conduction and luminescent properties of 1 are also discussed in detail. Moreover, the electrochemical impedance spectroscopy (EIS) measurements show a conductivity (1.9 × 10−4 S cm−1 at 65 °C and 95% relative humidity (RH)), with an activation energy of 0.41 eV for 1. The mechanism of proton conduction for 1 is proved to be the vehicular mechanism. [ABSTRACT FROM AUTHOR]

In the last three decades, the air pollution is the main problem to affecthumanhealth and the environment in China and its contaminants include SO2, NH3, H2S,NO2,NOand CO. In thiswork,we employed grand canonical Monte Carlo simulations to investigate the adsorption capability of metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) for these toxic gases. Eighty-nine MOFs and COFs were studied, and top-10 adsorption materials were screened for each toxic gas at room temperature.Dependence of the adsorption performance on the geometry and constructed element of MOFs/COFs was determined and the adsorption conditions were optimised. The open metal sites have mainly influenced the adsorption of NH3, H2S, NO2 and NO. Especially, the X-DOBDC and XMOF- 74 (X = Mg, Co, Ni, Zn) series of materials containing open metal sites are all best performance for adsorption of NH3 to illustrate the importance of electrostatic interaction. Our simulation results also showed that ZnBDC and IRMOF-13 are good candidates to capture the toxic gases NH3, H2S, NO2, NO and CO. This work provides important insights in screening MOF and COF materials with satisfactory performance for toxic gas removal. [ABSTRACT FROM AUTHOR]

Porous solid adsorbents have received considerable attention as a promising alternative to the traditional cryogenic distillation for separating olefin/paraffin mixtures. In this work, we studied pure components as well as ethylene/ethane and propylene/propane binary mixtures uptakes and selectivities at 318 K and 1 bar into metal-organic frameworks Ni2(dobdc) and Ni2(m-dobdc) using GCMC simulations. We used DFT method to modify the potential model of carbon-carbon double bond in unsaturated hydrocarbons. GCMC results show that ethylene and ethane uptakes on Ni2(m-dobdc) are higher than that of Ni2(dobdc) but propylene and propane uptakes are equal in Ni2(m-dobdc) and Ni2(dobdc). Also, Ni2(m-dobdc) has higher selectivity than Ni2(dobdc) for separation of ethylene/ethane and propylene/propane mixtures. [ABSTRACT FROM AUTHOR]

The composites of a copper-based metal-organic framework (HKUST-1) in the presence of graphite oxide (GO) were synthesized via a solvothermal method to remove thiophene (TP). The prepared GO/HKUST-1 composites were characterization by N2adsorption-desorption, XRD, SEM. The desulfurization performance of TP from the model fuels by GO/HKUST-1 with different content of GO was investigated. Most importantly, under the optimum adsorptive conditions, the composite material 1.75%GO/HKUST-1 exhibited excellent adsorption capacity of 60.67 mg/g, which was attributed to the highest surface area and porosity. [ABSTRACT FROM PUBLISHER]

The adsorption of CO2 on the metal-organic framework, Zn(ADC) · DMSO, is studied using density functional-based tight-binding calculations with empirical dispersion correction (DFTB-D). Validation calculations predict bulk structure parameters that are consistent with published X-ray structure data for the material. The method is further validated by showing that DFTB-D predicts surface structures and CO2 binding energies in good agreement with the results of DFT/PW91-D calculations for both Zn(ADC) · DMSO and Cu(BTC) · 3H2O. A corrugated 1 0 0 surface of Zn(ADC) · DMSO is proposed that avoids cleaving through any aromatic rings to form the slab when studying the surface adsorption of CO2. DFTB-D calculations of CO2/surface interactions are combined with an enhanced Langmuir-type adsorption model to investigate the adsorption efficiency of CO2 on the Zn(ADC) · DMSO surface. The dependence of this adsorption on particle size and shape, and its sensitivity to errors in the predicted binding energy on the order of the anticipated accuracy of the calculated binding energies are discussed. By comparison to DFT/PW91-D calculations, we conclude that DFTB-D is a cost-effective and reliable tool to predict adsorption behaviour for MOFs of this type. Finally, it is found that for this newly synthesised Zn · ADC MOF to attain a specific CO2 adsorption capacity comparable to that of conventional porous MOFs, its particle size must be decreased to the nanometer level. [ABSTRACT FROM AUTHOR]

In this work, the adsorption of acetylene and its binary mixture with methane on MOF-5, HKUST-1 and MOF-505 was studied using Grand Canonical Monte Carlo molecular simulations. The preferred adsorption sites of acetylene and methane molecules into metal–organic frameworks (MOFs) were investigated. The simulated adsorption isotherms of acetylene on MOF-5 and MOF-505 agreed well with the experimental ones without any reparameterisation of the potential parameters but for HKUST-1 the interaction parameters of the acetylene and copper ion were reparameterised. Comparisons of the calculated adsorption isotherms of acetylene in the studied MOFs showed that the MOF-5 had the lowest adsorption capacity. Our results revealed that guest molecules were most adsorbed on the entrance windows of the octagon pore of HKUST-1, while the preferred adsorption sites were large pores and on the metal ion cluster of MOF-505 and MOF-5, respectively. Adsorption of binary mixtures of methane and acetylene on MOF-5, HKUST-1 and MOF-505 revealed that acetylene adsorption is higher than that of methane. Finally, the results showed that C2H2/CH4selectivity values on HKUST-1 are significantly higher than on MOF-505 and MOF-5. The preferred adsorption sites of acetylene and methane in an equimolar binary mixture were calculated and discussed. [ABSTRACT FROM PUBLISHER]

Recently, metal-organic frameworks (MOFs) have been gaining attention as attractive support materials for the immobilization of proteins. They possess well-ordered pore structures, aperture channel distributions, great surface area, high stability, and can be modified with various functional groups. In this review, we present an overview of the reported fabrication methods of these materials along with the advantages and limitations of different approaches to immobilizing enzymes using MOF materials as support. [ABSTRACT FROM PUBLISHER]

Adsorption equilibrium, thermodynamics, and kinetics of CH4, N2, and CO2were investigated by volumetric-chromatographic and inverse gas chromatographic (IGC) methods on the Al-BDC MOF. The binary adsorption data from the volumetric-chromatographic experiments represents that the Al-BDC MOF has a high CO2/CH4selectivityca.11 and a CH4/N2selectivityca.4.3 at 303 K, and appears to be a good candidate for the CH4separation. The initial adsorption heats of CH4, N2, and CO2on the Al-BDC MOF were determined to be 15.3, 11.5, and 32.2 kJmol−1by IGC method, respectively. Moreover, the micropore diffusivities of N2, CH4and CO2in the Al-BDC MOF at 303 K were also estimated to be 1.58 × 10−7cm2/s, 7.04 × 10−8cm2/s, and 3.95 × 10−9cm2/s, respectively. The results indicate that micropores play a crucial role in the adsorptive separation of the CH4/N2and CH4/CO2mixtures, and the IGC method is a validity manner to estimate the thermodynamic and kinetic parameters of MOF adsorbents. [ABSTRACT FROM PUBLISHER]

Metal-organic frameworks (MOFs) with coordinatively unsaturated sites (CUS) offer interesting possibilities for tuning the affinity of these materials towards certain adsorbates, potentially increasing their selectivity and storage capacity. From a modelling point of view, however, they pose a significant challenge due to the inability of conventional force-fields for dealing with these specific interactions. In this paper, we review recent developments in the application of quantum-mechanical (QM) methods and classical molecular simulations to understand and predict adsorption in MOFs with CUS. We find that hybrid approaches that incorporate QM-based information into classical models are able to provide dramatically improved adsorption predictions relative to conventional force-fields, while yielding a realistic description of the adsorption mechanism in these materials. [ABSTRACT FROM PUBLISHER]

We examined the effects of electrostatic interactions on gas adsorption and permeability of metal organic framework (MOF) membranes and MOF-filled mixed matrix membranes (MMMs) for CO2/CH4, CO2/N2and H2/CO2separations using molecular simulations. Adsorption isotherms and diffusion rates of CO2, CH4, N2and H2in several MOFs were computed using grand canonical Monte Carlo and equilibrium molecular dynamics simulations, respectively. Gas permeability and selectivity of pure MOF membranes and MOF-filled MMMs were then evaluated using theoretical permeation models. The accuracy of our molecular simulations was validated by comparing theoretical predictions for gas permeability and selectivity of MOF-filled MMMs with the available experimental data. We then used the same modelling approach to predict the performance of new MOF-filled MMMs in CO2/CH4, CO2/N2and H2/CO2separations. Promising MOF/polymer combinations which offer high selectivity and permeability relative to pure polymer membranes were identified. Our results showed that including electrostatic interactions between adsorbate molecules and MOF atoms is crucial for modelling pure MOF membranes but has less significance for modelling MOF-filled MMMs whenever the MOF volume fraction, ≤ 0.30. This result suggests that preliminary screening studies of MOF-filled MMMs can be carried out without assigning partial charges to MOF atoms. [ABSTRACT FROM AUTHOR]

We briefly review the concept of temperature-loading phase diagram that we derived from an osmotic statistical ensemble analysis of the adsorption-induced structural transitions observed in the MIL-53 family of metal-organic framework nanoporous materials. We highlight the generic nature of this diagram and comment on the occurrence of breathing transitions depending on the guest fluid, the framework functionalisation and the nature of the metal centre. [ABSTRACT FROM AUTHOR]

Grand canonical Monte Carlo and equilibrium molecular dynamics simulations were used to assess the performance of an rht-type metal–organic framework (MOF), Cu-TDPAT, in adsorption-based and membrane-based separation of CH4/H2, CO2/CH4 and CO2/H2 mixtures. Adsorption isotherms and self-diffusivities of pure gases and binary gas mixtures in Cu-TDPAT were computed using detailed molecular simulations. Several properties of Cu-TDPAT such as adsorption selectivity, working capacity, diffusion selectivity, gas permeability and permeation selectivity were computed and compared with well-known zeolites and MOFs. Results showed that Cu-TDPAT is a very promising adsorbent and membrane material especially for separation of CO2 and it can outperform traditional zeolites and MOFs such as DDR, MFI, CuBTC, IRMOF-1 in adsorption-based CO2/CH4 and CO2/H2 separations. [ABSTRACT FROM AUTHOR]

Considering the amount of colored waste water generated from many industries (textile, leather, paper, printing, dyestuff, and plastic) that are sent to various water bodies and the ecosystem, the search for efficient and better methods of purification still continues. With the recent research into metal organic frameworks (MOFs), there is a steady growing interest worldwide for their various applications. This article presents a review of MOFs, their application in dye adsorption and their various challenges and future prospects. It was concluded that with the current interest, research and development for various applications, there are possibilities which will bring to limelight more laboratory, industrial and environmental usage of MOFs as dye adsorbents. [ABSTRACT FROM PUBLISHER]

In this article, we present a set of computational tools for systematic characterisation of ordered and disordered porous materials. These tools include calculation of the accessible surface area and geometric pore size distribution, analysis of the structure connectivity and percolation analysis of the porous space. We briefly discuss the algorithms behind these calculations. To demonstrate the capabilities of the tools and the type of insights that can be gained from their application, we consider a series of case studies. These case studies include small molecular fragments, several crystalline metal-organic materials, and variants of these materials with induced defects and disorder in their structure. The simulation package is available upon request. [ABSTRACT FROM PUBLISHER]

Metal-organic framework MIL-53(Al) pellets were tested for the selective adsorption and separation of xylene isomers, in liquid phase and using n-heptane as eluent. The objective of this work is to assess relevant data for a posterior xylene isomers separation process design. In order to complete this study, single and multi-component breakthrough experiments were performed at 313 K, in the presence of n-heptane. MIL-53(Al) presented a preference for o-xylene over m-xylene and p-xylene in all experiments. The selectivities of 2.0 were obtained for o-xylene over m-xylene and over p-xylene. It is concluded that MIL-53(Al) may be used for separating o-xylene from the other xylene isomers, using n-heptane as desorbent. Supplemental materials are available for this article. Go to the publisher's online edition of Separation Science & Technology to view the free supplemental file. [ABSTRACT FROM AUTHOR]

The channels of the cobalt formate frameworks consist of one-dimensional channels that have a zig-zag configuration. Propane (C3) has a length that commensurates with the channel segment length; longer n-alkanes such as n-butane (nC4), n-pentane (nC5) and n-hexane (nC6) have conformations that straddle two channel segments. Configurational-bias Monte Carlo (CBMC) simulations show that the adsorption strength of C3 is higher than that of n-butane (nC4) and n-pentane (nC5); this unusual hierarchy is a direct consequence of the commensurate-incommensurate adsorption. CBMC simulations also reveal the possibility of separating C3-nC6, C3-nC4, nC4-nC6 and nC4-nC5 liquid mixtures for which the adsorbed phase contains predominantly the shorter alkane. Molecular dynamics simulations show that the hierarchy of self-diffusivities is non-monotonic and is the mirror image of the hierarchy of adsorption strengths. [ABSTRACT FROM AUTHOR]