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Lanthanide metal–organic frameworks (Ln-MOFs) combine the lanthanide luminescence characteristics and the advantages of porous materials, which can be used in various research fields by exploring their multifunctional properties. A three-dimensional water-stable and high-temperature resistant Eu-MOF [Eu(H2O)(HL)]·0.5MeCN·0.25H2O (H4L = 4-(3,5-dicarboxyphenoxy)isophthalic acid), demonstrating a high photoluminescence quantum yield, was synthesized and structurally characterized. In terms of luminescence, the Eu-MOF exhibits excellent selectivity and quenching sensing for Fe3+ (LOD = 4.32 μM) and ofloxacin, as well as color modulation with Tb3+ and La3+ to develop white LED components with high illumination efficiency (color rendering index, CRI = 90). On the other hand, narrow one-dimensional channels of the Eu-MOF decorated with COOH groups enable a rare reverse adsorption selectivity in a CO2/C2H2 gas mixture. In addition, the protonated carboxyl groups in the Eu-MOF provide an efficient conducting platform for proton transfer with a conductivity value of 8 × 10−4 S cm−1 at 50 °C and RH 100%. [ABSTRACT FROM AUTHOR]

Since its first industrial production in 1890s, acetylene has played a vital role in manufacturing a wide spectrum of materials. Although current methods and infrastructures for various segments of acetylene industries are well‐established, with emerging functional porous materials that enabled desired selectivity toward target molecules, it is of timely interest to develop new efficient technologies to promote safer acetylene processes with a higher energy efficiency and lower carbon footprint. In this Minireview, we, from the perspective of materials chemistry, review state‐of‐the‐art examples of advanced porous materials, namely metal–organic frameworks and decorated zeolites, that have been applied to the purification and storage of acetylene. We also discuss the challenges on the roadmap of translational research in the development of new solid sorbent‐based separation technologies and highlight areas which require future research efforts. [ABSTRACT FROM AUTHOR]

Since its first industrial production in 1890s, acetylene has played a vital role in manufacturing a wide spectrum of materials. Although current methods and infrastructures for various segments of acetylene industries are well‐established, with emerging functional porous materials that enabled desired selectivity toward target molecules, it is of timely interest to develop new efficient technologies to promote safer acetylene processes with a higher energy efficiency and lower carbon footprint. In this Minireview, we, from the perspective of materials chemistry, review state‐of‐the‐art examples of advanced porous materials, namely metal–organic frameworks and decorated zeolites, that have been applied to the purification and storage of acetylene. We also discuss the challenges on the roadmap of translational research in the development of new solid sorbent‐based separation technologies and highlight areas which require future research efforts. [ABSTRACT FROM AUTHOR]

This study focuses on the preparation of HKUST‐1@SiO2 composite and its application as an adsorbent for the removal of chlorpyriphos from water environment. For studying the physical properties, synthesized HKUST‐1@SiO2 was characterized using FTIR, XRD, BET, FE‐SEM and EDS. Characterization results indicated that the interaction of HKUST‐1 with SiO2 resulted in improvement of various physicochemical properties. The integration of HKUST‐1 and SiO2 resulted in improved adsorption of chlorpyrifos, where maximum 85 % removal was obtained at 30 °C. The adsorption data was best fitted into Langmuir isotherms, and it was in well accordance with pseudo second order kinetic model. High adsorption efficiency of the composite is related to its high pore volume which results in high number of adsorption sites on silica surface for the attachment of various functional groups present in chlorpyriphos. [ABSTRACT FROM AUTHOR]

Nowadays, there are many reliable characterization techniques for the study of adsorption properties in gas phase. However, the techniques available for the study of adsorption processes in solution, rely on indirect characterization techniques that measure the adsorbate concentration remaining in solution. In this work, we present a sensing method based on the magnetic properties of metal-organic frameworks (MOFs) containing paramagnetic metal centres, which stands out for the rapidity, low cost and in situ direct measurement of the incorporated adsorbate within the porous material. To illustrate this sensing technique, the adsorption in solution of four MOFs have been characterized: MIL-88A(Fe), MOF-74(Cu, Co) and ZIF-67(Co). Our simple and efficient method allows the direct determination of the adsorbed mass, as well as the measurement of adsorption isotherm curves, which we hope will greatly advance the study of adsorption processes in solution, since this method is independent of the chemical nature of the adsorbate that often makes its quantification difficult. Techniques capable of measuring adsorption processes in solution typically rely on indirect methods. Here, a magnetic sustentation technique is shown to rapidly and directly measure the mass of adsorbates in four paramagnetic metal–organic framework materials in solution. [ABSTRACT FROM AUTHOR]

Porous materials with high adsorption capacity can enhance the efficiency of water-based adsorption heat transformation systems. The composites salt in porous matrix (CSPM) are considered to be very promising materials. In this paper, the UIO-66-NH 2 and UIO-66-NO 2 metal-organic framework were used as the porous matrix to synthesize composites with CaCl 2 as the hygroscopic salt. The water adsorption and desorption performance of the composite materials were studied, and the cycle stability was investigated in a continuous adsorption-desorption experiment. As a result, the hydrophilic UIO-66 based composites exhibited higher water adsorption and heat storage capacity. CaCl 2 @UIO-66-NH 2 achieved a water adsorption capacity of 0.84 g/g at 60% relative humidity (RH) and an energy storage density of 1858 J/g. In addition, the hydrophilic UIO-66 based composites exhibited excellent cycle stability, with the quality decreasing by less than 5% after ten adsorption-desorption cycles. By introducing hydrophilic functional groups, the adsorption capacity, adsorption rate, and thermal storage capacity of CSPMs were improved. [Display omitted] • The hydrophilic functionalized UIO-66 based composites exhibit enhanced water absorption properties. • The hydrophilic functionalized samples have higher energy storage densitywith CaCl 2 @UIO-66-NH 2 reaching 1858J/g. • All samples exhibited good cycle stability and the water adsorption quantity decreased by less than 5% after 10 cycles. [ABSTRACT FROM AUTHOR]

Nowadays, sustaining the atmosphere and protecting it from global warming are recognized as the main concerns of the planet. This problem has been addressed through the development of a number of different carbon capture and sequestration approaches. Lately, metal‐organic framework (MOF) has emerged as the most auspicious CO2 adsorption and conversion material. This novel class of porous material has demonstrated tremendous potential for gas separation technologies, particularly CO2 adsorption and conversion due to their remarkable characteristics. Therefore, the present review attempted to provide current understanding of the CO2 adsorption and conversion performance over MOF‐based materials. This review paper discussed the type and properties of the MOF, effect of metal and ligand on MOF's properties, and various applications of MOF. Furthermore, future insights were proposed for better design and development of MOF‐based materials for CO2 applications. [ABSTRACT FROM AUTHOR]

A Zn–BTB metal–organic framework structure was synthesized by the solvothermal method; it is characterized by micropore volume W0 = 0.67 cm3/g, effective radius of micropores х0 = 0.67 nm, and standard characteristic energy of benzene-vapor adsorption Е0 = 18.0 kJ/mol. The theory of volume filling of micropores was used to calculate the methane-adsorption equilibria on the synthesized Zn–BTB sample at temperatures over the range from 243 to 313 K and pressures up to 35 MPa; the differential molar isosteric heats of adsorption were evaluated. The maximum value of methane adsorption amounts to ~14.5 mmol/g at a pressure of 8 MPa and a temperature of 243 K. [ABSTRACT FROM AUTHOR]

[Display omitted] • CO 2 adsorption using MOFs with functional groups (FGs) is thoroughly reviewed. • FGs, especially polar ones, loaded on MOFs are very efficient in CO 2 adsorption. • Adsorption capacity, selectivity, and heat of adsorption could be increased with polar FGs. • The favorable contributions could be explained with various electrostatic interactions. • A prospect on CO 2 adsorption using MOFs with FGs is provided for a future study. Selective and effective capture of CO 2 from off-gases or even from the atmosphere is very important to prevent global warming. Recently, CO 2 adsorption using porous materials has attracted much attention because of its high efficiency and the low corrosiveness of porous adsorbents. Especially, metal–organic frameworks (MOFs, typical porous materials) have been deeply studied for CO 2 adsorption because MOFs have strong points like very high porosity, designable structure, and ready modification. Functionalized MOFs have been very useful in CO 2 adsorption in increasing the adsorption capacity, selectivity, and heat of adsorption although the porosity could be reduced by loading functional groups (FGs) onto the MOFs. In this review, we analyzed comprehensively the contribution of FGs (excluding the well-known amino group) of MOFs to CO 2 adsorption under low pressure. Although there have been a few reports to compare the contribution of some FGs to CO 2 adsorption, there are various contradictory results; moreover, to the best of our knowledge, there has been no comprehensive review that analyses the relative contribution of FGs to the adsorption so far. It can be concluded that FGs, especially the ones (such as -OLi, -SO 3 Li, –NO 2 , and -SO 3 H) that can increase the dipole moment of linkers of MOFs, are highly effective in CO 2 adsorption mainly because of effective electrostatic interactions. Finally, prospects were given, based on the summary of this review, for future research. [ABSTRACT FROM AUTHOR]

Despite much intense investigation on the C2H2/CO2 separation, the trade‐off between the adsorption capacity and separation selectivity is still tricky. To overcome the dilemma, we have rationally synthesized an ultra‐stable fluorinated hybrid porous material SIFSIX‐Cu‐TPA with the ith‐d topology. Completely differing from the famous pillar‐layer fluorinated materials, SIFSIX‐Cu‐TPA possesses a unique pillar‐cage structure, in which the SiF62− anions cross‐link two adjacent metal nodes as pillars to stabilize the three‐dimensional framework constructed by icosahedral and tetrahedral cages. As anticipated, SIFSIX‐Cu‐TPA has high BET surface area (1330 m2 g−1) as well as high C2H2 uptake (185 cm3 g−1 at 298 K and 1 bar). At the same time, due to the obvious difference in the adsorption performance of CO2 and C2H2 especially in the low pressure area, SIFSIX‐Cu‐TPA also exhibits an excellent C2H2/CO2 separation performance (breakthrough time up to 68 min g−1 at 298 K and 1 bar). [ABSTRACT FROM AUTHOR]

Despite much intense investigation on the C2H2/CO2 separation, the trade‐off between the adsorption capacity and separation selectivity is still tricky. To overcome the dilemma, we have rationally synthesized an ultra‐stable fluorinated hybrid porous material SIFSIX‐Cu‐TPA with the ith‐d topology. Completely differing from the famous pillar‐layer fluorinated materials, SIFSIX‐Cu‐TPA possesses a unique pillar‐cage structure, in which the SiF62− anions cross‐link two adjacent metal nodes as pillars to stabilize the three‐dimensional framework constructed by icosahedral and tetrahedral cages. As anticipated, SIFSIX‐Cu‐TPA has high BET surface area (1330 m2 g−1) as well as high C2H2 uptake (185 cm3 g−1 at 298 K and 1 bar). At the same time, due to the obvious difference in the adsorption performance of CO2 and C2H2 especially in the low pressure area, SIFSIX‐Cu‐TPA also exhibits an excellent C2H2/CO2 separation performance (breakthrough time up to 68 min g−1 at 298 K and 1 bar). [ABSTRACT FROM AUTHOR]

• ZJU-194a features the unique flexible-robust network. • ZJU-194a affords high adsorptive C 2 H 2 /C 2 H 4 selectivity. • The distinct host–guest affinity accounts for different gate open-close states. The removal of trace acetylene (C 2 H 2) from raw ethylene (C 2 H 4) stream is critical for production of polymer-grade chemicals. We herein report a perchlorate-coordinated metal–organic framework (ZJU-194) featuring flexible-robust network for efficient C 2 H 2 /C 2 H 4 separation. The distinct-different host–guest affinity accounts for two-step gate-opening adsorption of C 2 H 2 , but gate-close of C 2 H 4. It thus affords very high adsorptive selectivity (28.9) at ambient conditions, endowing ZJU-194 among one of the top-performing porous materials for C 2 H 2 /C 2 H 4 separation. [ABSTRACT FROM AUTHOR]

[Display omitted] • The capacity of an adsorbent depends on its surface area size and active sites. • Desulfurization adsorbents include carbon, molecular sieves, metal oxides and MOFs. • Active components introduced into the adsorbents are metals, alkalis, and organics. • Sulfocompounds are converted to S, SO 4 2-, SO 3 2-, etc. at the active site. • The adsorbents can be regenerated by heat, solvent immersion and Step-down/vacuum. Sulfocompounds in flue gas emitted by various industries, not only affect the stability of pipelines and subsequent devices but also cause air pollution when discharged into the atmosphere. Due to the advantages of low cost and good recyclability, porous materials are usually applied to adsorb both organic and inorganic sulfocompounds. Inorganic sulfocompounds can easily interact with porous adsorbents by polar interaction, acid-base interactions, or metal coordination adsorption. Organic sulfocompounds with high reaction energy are more likely to be immobilized by physisorption. Among the adsorption materials, carbon materials and molecular sieves have well-developed pores and a huge specific surface area to build different active sites. Metal active sites (–OH, adsorbed oxygen, lattice oxygen) in metal oxides are the main sites for their adsorption effects, and MOFs materials, as metal crystalline materials with periodic structure, have both large specific surface area and abundant metal sites. When the porous material is saturated with adsorption, it is necessary to keep the recycling of the material. Correspondingly, in this work, the desulfurization mechanisms including both physical and chemical interaction were elucidated firstly, based on which the adsorbent materials (i.e., carbon-based materials, molecular sieves, metal oxides, metal organic frameworks) were then summarized from both aspects of their textural properties and their application in desulfurization. The applicability of three ways ((i.e., thermal regeneration, solvent regeneration, and pressure reduction/vacuum regeneration) for regenerating porous materials are summarized. It is expected to provide some advanced guidance for researchers in the adsorption of sulfocompounds in flue gas. [ABSTRACT FROM AUTHOR]

The adsorption of 2,4-dichlorophenoxyacetic acid (2,4-D) from aqueous solutions on different porous materials was studied. The materials included micro- and mesoporous carbon matrices of different genesis and metal-organic frameworks (MOFs) of the MIL type such as microporous matrices MIL-53(Al) (AlOHbdc, bdc = benzene-1,4-dicarboxylate) and NH2-MIL-53(Al) (AlOHbdc, abdc = 2-aminobenzene-1,4-dicarboxylate), as well as mesoporous matrix NH2-MIL-101(Al) (Al3O(abdc)3). It is found that the efficiency of liquid phase adsorption is affected by the texture and functionality of the studied materials, whereas in the case of MOFs, the adsorption efficiency is also under the influence the framework flexibility. The MOF materials and mesoporous carbon matrices show a higher adsorption rate than microporous carbon matrices. The flexible microporous MIL-53(Al) framework and microporous coconut shell activated carbon (CSAC) exhibit the highest adsorption capacity with respect to 2,4-D. [ABSTRACT FROM AUTHOR]

Amorphous metal–organic frameworks (amMOFs) with a partially collapsed structure are a new category of porous hybrid materials. Here, solid‐state amorphization of ZIF‐8 was achieved by mechanical compression at 0.75 GPa. The compression‐induced amorphous ZIF‐8 (amZIF‐8) had a collapsed structure, but retained partial porosity. Benefiting from the deformed channel, the resultant amZIF‐8 exhibited preferable adsorption of C3H6, resulting in higher thermodynamic adsorption selectivity of C3H6/C3H8 (6.72) than the crystalline counterparts (1.06). Further, amZIF‐8 achieved complete separation of an equimolar C3H6/C3H8 mixture with the first breakthrough of C3H8. amZIF‐8 also displayed an enhancement in CO2/N2 and CO2/CH4 adsorption selectivities. More importantly, a self‐standing amZIF‐8 membrane with boundary‐free microstructure was constructed for the first time, and exhibited separation potential for H2/CH4, CO2/N2, CO2/CH4, and C3H6/C3H8 with ideal selectivities of 14.79, 12.83, 16.23, and 2.67, respectively. [ABSTRACT FROM AUTHOR]

Porous materials such as MOFs are interesting candidates for gas separation and storage. An important parameter to gain deeper insights to the adsorption process of an adsorptive on an adsorbent is the isosteric enthalpy of adsorption, ΔHads which is defined as the heat to be released/required when an adsorptive binds to/detaches from the solid surface of an adsorbent. Two or three adsorption isotherms at different but close temperatures with ΔT ≤ 20 K for two and ΔT ≈ 10 K for three isotherms are the basis to derive the isosteric enthalpy of adsorption through the Clausius–Clapeyron approach or the virial analysis. This Perspective presents the procedure of the common (dual-site) Freundlich–Langmuir fit/Clausius–Clapeyron approach and the virial fit of the isotherms with usable Excel sheets and Origin files for the subsequent derivation of ΔHads. Exemplary adsorption isotherms of CO2, SO2 and H2 at two temperatures on MOFs are analyzed. The detailed computational description and comparison of the Clausius–Clapeyron approach and the virial analysis to determine ΔHads outlines the limitations of the two methods with respect to the available experimental data, especially at low pressure/low uptake values. It is emphasized that no extrapolation beyond the experimental data range should be done. The quality of the important and underlying isotherm fits must be checked and ensured with logarithmic-scale n/p isotherm plots for the (dual-site) Freundlich–Langmuir fit in the low-pressure region and through low standard deviations for the coefficients in the virial analysis. [ABSTRACT FROM AUTHOR]

In a world where capture and separation processes represent above 10% of global energy consumption, novel porous materials, such as Metal-Organic Frameworks (MOFs) used in adsorption-based processes are a promising alternative to dethrone the high-energy-demanding distillation. Shape and size tailor-made pores in combination with Lewis acidic sites can enhance the adsorbate-adsorbent interactions. Understanding the underlying mechanisms of adsorption is essential to designing and optimizing capture and separation processes. Herein, we analyze the adsorption behaviour of light hydrocarbons (methane, ethane, ethylene, propane, and propylene) in two synthesized copper-based MOFs, Cu-MOF-74 and URJC-1. The experimental and computational adsorption curves reveal a limited effect of the exposed metal centers on the olefins. The lower interaction Cu-olefin is also reflected in the calculated enthalpy of adsorption and binding geometries. Moreover, the diamond-shaped pores' deformation upon external stimuli is first reported in URJC-1. This phenomenon is highlighted as the key to understanding the adsorbent's responsive mechanisms and potential in future industrial applications. [Display omitted] [ABSTRACT FROM AUTHOR]

The formation of metal–organic frameworks (MOFs) under given reaction conditions depends on various factors including reaction duration, temperature, used solvent, system pH, and others. Among them, the reaction duration is relatively less investigated. In this work, based on a Cu(ii)-MOF system, the reaction duration was found to play an important role in directing the formation of two different products, (NH2(CH3)2)[Cu12(DDPN)6(H2O)10Cl] (BUT-301) on shorter reaction time and (NH2(CH3)2)2[Cu(DDPN)] (BUT-302) on longer reaction time, when CuCl2 reacted with 3,5-di(3,5-dicarboxylphenyl)nitrobenzene (H4DDPN) in a DMA/MeOH mixed solvent at 120 °C. With increasing the reaction duration, BUT-301 can transform into BUT-302. Both MOFs have three-dimensional (3D) framework structures. BUT-301 is constructed from paddle-wheel Cu2(COO)4 units and DDPN4– ligands as four-connected linkers, while BUT-302 is assembled from mononuclear Cu(ii) centers connecting the ligands as also four-connected linkers but in a monodentate coordination fashion. N2 adsorption confirmed that both MOFs are porous materials with the Brunauer–Emmett–Teller (BET) surface areas of 1953 and 561 m2 g−1, respectively. Interestingly, both BUT-301 and -302 show selective adsorption properties of C3H4 over C3H6. The C3H4/C3H6 adsorption selectivities were calculated to be 1.9 and 4.4 at 0.1 bar and 298 K by the ideal adsorbed solution theory (IAST) for a 1 : 99 C3H4/C3H6 mixture, respectively. [ABSTRACT FROM AUTHOR]

A new three-dimensional (3D) porous Mn(ii)-based metal–organic framework [Mn4(L)2(H2O)4]n·4DMF·H2O (1) has been synthesized using Mn(ii) and the rigid 2,6-di(2′,5′-dicarboxylphenyl)pyridine (H4L) ligand under solvothermal conditions. Structural analysis revealed that MOF 1 is an open framework with exposed active nitrogen atoms and rectangular-shaped channels along the b axis (with effective aperture sizes of 11.3 × 8.8 Å2 and 10.7 × 8.7 Å2). Gas sorption behaviors showed that MOF 1 has a relatively high capacity and selectivity for CO2 over CH4. Thus, the CO2 cycloadditions were studied using different epoxides, displaying the high efficiency of the catalyst. It was also found that MOF 1 shows rapid adsorption for the organic dyes. Therefore, MOF 1 should be explored as a multifunctional porous material for gas separation, catalysis and dye adsorption. [ABSTRACT FROM AUTHOR]

Abstract Environmental pollution is one of the most serious problems facing mankind today, and has attracted widespread attention worldwide. The burgeoning class of crystalline porous organic framework materials, metal–organic frameworks and covalent organic frameworks present promising application potential in areas related to pollution control due to their interesting surface properties. In this review, the literature of the past five years on the adsorptive removal of various hazardous materials, mainly including heavy metal ions, harmful gases, organic dyes, pharmaceutical and personal care products, and radionuclides from the environment by using COFs and MOFs, is summarized. The adsorption mechanisms are also discussed to help understand their adsorption performance and selectivity. Additionally, some insightful suggestions are given to enhance the performance of MOFs and COFs in the adsorptive removal of various hazardous materials. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Abstract A highly porous 3D metal-organic framework {H 3 [(Cd 4 Cl) 3 (ttpa) 8 (H 2 O) 12 ]⋅nH 2 O} ∞ (1) with a 3,8-connected framework (H 3 ttpa = tris-[4-tetrazolylphenyl]amine) was prepared by in situ chemical synthesis using solvothermal method. With the open metal sites, the complex 1 can act as an efficient adsorbent for the removal of benzothiophene (BT) and dibenzothiophene (DBT) from isooctane. Graphical abstract Image 1 Highlights • A highly porous 3D MOF {H3[(Cd4Cl)3(ttpa)8(H2O)12]⋅nH2O}∞ (1) with a 3,8-connected framework is successfully synthesized. • The Complex 1 possess the open metal sites in MOFs. • The complex 1 shows efficient adsorption for the removal of benzothiophene and dibenzothiophene. [ABSTRACT FROM AUTHOR]

A series of furan/thiophene-derived Cr-MIL-101s were obtained via visible-light-mediated C–C bond-forming catalysis within photosensitizing porous materials. The guest trapping process was achieved under very mild and metal-free conditions, affording newly functionalized MOFs with more π–π stacking, hydrogen bonding properties and excellent adsorption capacity in removing herbicides from aquatic environments. [ABSTRACT FROM AUTHOR]

Abstract Highly porous composites were synthesized via facile crystallization of a metal-organic framework (MOF) in mesopores of a three-dimensional (3D) graphene (MG). First, MG was prepared via facile thermal exfoliation of graphite oxide in air, which enabled sufficient separation of graphene sheets in the form of an interconnected 3D structure. Next, aluminum-based MOF [MOF520: Al 8 (OH) 8 (BTB) 4 (HCOO) 4 , BTB = 4,4′,4"-benzene-1,3,5-tryil-tribenzoate] was predominantly crystallized in mesopores of 3D structure having a large pore volume. The resulting MG-MOF composites possessed specific surface areas and pore volumes between those of MG (640 m2/g and 3.0 cm3/g) and MOF (3160 m2/g and 1.3 cm3/g). The composite consisting of MG and MOF with a weight ratio of 1:2 showed almost twice-larger benzene adsorption capacity, i.e., 24.5 mmol/g at 20 °C and relative pressure close to unity, in comparison to that of pure MOF. Although at the same conditions the pure MG captured an ultrahigh amount of benzene, i.e., 33.6 mmol/g, adsorption of this adsorbate at low and moderate relative pressures was much lower than that on pure MOF. Thus, the MG-MOF composites featured much better benzene adsorption performance in a wide range of relative pressures as compared to pure MG and MOF, respectively. Additionally, the composites featured better thermal stability in comparison to the pristine MOF. The use of MG in this synthesis method afforded the well-dispersed, small crystals of MOF, which is essential for the design of MOF-based composites. Graphical abstract Image 1 Highlights • Crystallization of MOF in mesopores of a three-dimensional graphene. • Enhancement of C 6 H 6 adsorption by adding mesoporous graphene to MOF. • Ultrahigh C 6 H 6 adsorption of 24.5 mmol/g on graphene-MOF composite at 20 °C. [ABSTRACT FROM AUTHOR]

Highlights • Metal–organic frameworks are porous materials which show many potential applications. • Germany-based researchers have provided significant contributions to this field. • Comprehensive review of unique synthesis approaches and characterization methods. • Advanced functions and the performance of these promising materials are highlighted. Abstract Metal–organic frameworks (MOFs) are constructed from a combination of inorganic and organic units to produce materials which display high porosity, among other unique and exciting properties. MOFs have shown promise in many wide ranging applications, such as catalysis and gas separations. In this review, we highlight MOF research conducted by Germany-based research groups. Specifically, we feature approaches for the synthesis of new MOFs, high-throughput MOF production, advanced characterization methods and examples of advanced functions and properties. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs), which are inorganic–organic hybrid porous materials prepared from metal ion/clusters and multidentate organic ligands, have evolved to be next‐generation utility materials because of their usability in diverse applications. These porous materials, with excellent chemical stability and a wide variety of functional groups, have demonstrated their utility to the area of capturing various types of hazardous metal ion pollutants. This conceptual review focuses on recent progress in reported MOFs as HgII and PbII adsorbents emphasizing the general concepts that have guided important developments in these area and their implications for future research. Also, we suggest our personal insights into future research opportunities in the area and we hope to encourage more researchers to engage in this new field of MOF‐based materials with the goal of environmental pollution management. MOFs are the goal! This Concept focuses on recent progress in reported MOFs as HgII and PbII adsorbents emphasizing the general principles that have guided important developments in these areas and their implications for future research. We also suggest our personal insights into future research opportunities in the area and we hope to encourage more researchers to engage in this new field of MOF‐based materials with the goal of environmental pollution management. [ABSTRACT FROM AUTHOR]

With the rapid increasing of the available number of novel porous materials, a straightforward and low-cost testing methodology to assess those suitable for near ambient temperature hydrogen storage applications is needed. In this work, we developed a new assessment methodology to quickly identify those porous materials potentially suitable for near ambient temperature hydrogen storage applications. We introduced the usable capacity map showing why the absolute adsorption capacity at the temperature of 77 K is not a good indicator to compare the material's storage performance. In fact, some porous material that shows low usable capacity at 77 K appear to be better adsorbent at a higher temperature. Moreover, we demonstrated that using quick cyclic adsorption isotherm or TDS is possible to easily individuate those materials that are the most suitable for near ambient temperature applications. Therefore, as a general result, we showed that among the three commercial activated carbon, used here as case study, the one with the higher content of ultramicroporosity is the most promising because the optimum operating temperature shifts towards ambient temperature. [ABSTRACT FROM AUTHOR]

A novel water stable porous metal–organic framework (MOF), [Cu3(OH)2(IBA)2(CH3COO)2]·DMA (1) (HIBA = 4-(imidazol-1-yl)-benzoic acid, DMA = N,N-dimethylacetamide), has been solvothermally synthesized and structurally characterized. The framework of compound 1 is constructed from rod SBUs with a new (5,8)-connected topology. Compound 1 exhibits exceptional chemical stability under various conditions (organic solvents, water, boiling water or pH = 1–8 acidic and basic aqueous solutions). Meanwhile, it exhibits good selectivity for CO2 over CH4 (6.6 for CO2/CH4 = 0.5/0.5 and 5.8 for CO2/CH4 = 0.05/0.95 under 1 bar at 298 K). The excellent stability of compound 1 is of extreme importance for its practical industrial applications. [ABSTRACT FROM AUTHOR]

Materials science of metal open frameworks is a state-of-the-art field for numerous applications, such as gas storage, sensors, and medicine. Two nanoporous frameworks, γ-Mg(BH4)2 and MIL-91(Ti), with different levels of structural flexibility, were examined with in situ X-ray diffraction guest adsorption-desorption experiments. Both frameworks exhibit a cooperative guest adsorption correlated with a lattice deformation. This cooperativity originates from the long-range interactions between guest molecules, mediated by elastic response of the host porous structure. The observed experimental scenarios are rationalized with a mean field Gorsky-Bragg-Williams (GBW) approach for the lattice-gas Ising model. The adjusted GBW model, in combination with in situ synchrotron powder diffraction, demonstrates an efficient experimental and phenomenological approach to characterize thermodynamics of the adsorption in MOFs not only for the total uptake but also for every specific guest site. [ABSTRACT FROM AUTHOR]

An accurate van der Waals force field (VDW FF) was derived from highly precise quantum mechanical (QM) calculations. Small molecular clusters were used to explore van der Waals interactions between gas molecules and porous materials. The parameters of the accurate van der Waals force field were determined by QM calculations. To validate the force field, the prediction results from the VDW FF were compared with standard FFs, such as UFF, Dreiding, Pcff, and Compass. The results from the VDW FF were in excellent agreement with the experimental measurements. This force field can be applied to the prediction of the gas density (H2, CO2, C2H4, CH4, N2, O2) and adsorption performance inside porous materials, such as covalent organic frameworks (COFs), zeolites and metal organic frameworks (MOFs), consisting of H, B, N, C, O, S, Si, Al, Zn, Mg, Ni, and Co. This work provides a solid basis for studying gas adsorption in porous materials. © 2017 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Magnetic porous carbon-based sorbent (MPCS) with core-shell structure was prepared from the pyrolysis of Fe III -modified MOF-5. The component, structure and surface properties of the as-obtained sorbent were investigated by Raman spectroscopy, X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. Sorption behaviors of five organic micropollutants (OMPs), such as atrazine, carbamazepine, bisphenol A, norfloxacin and 4-nitrophenol, onto the magnetic porous MPCS were studied in a batch system. The adsorption capacities of the five OMPs onto MPCS followed the order of 4-nitrophenol > norfloxacin > bisphenol A > carbamazepine > atrazine. All isotherms were fitted well by the Dubinin-Ashtakhov (DA) model, and the approximate site energy distributions were acquired. The possible adsorption mechanisms of the five OMPs onto as-prepared MPCS were discussed in detail. This study will aid in further understanding of interactions between the OMPs and MOF-derived carbon-based materials. [ABSTRACT FROM AUTHOR]

This work presents the construction of a porous lead-organic framework (UPC-10) with large channels of ∼24 Å. UPC-10 shows efficient adsorption of I2 and selective adsorption of some dyes containing the SO3− group. After the adsorption of dyes, UPC-10 exhibits a CO2 gas uptake ability. Furthermore, UPC-10 could be transformed into PbS in a H2S atmosphere, and the derived PbS manifests N2 and CO2 uptake abilities. [ABSTRACT FROM AUTHOR]

A flexible bipyridinium ligand has been introduced into a series of isomorphous metal-organic frameworks to yield porous materials with subtriangular 1D channel and cagelike pore space. The introduction of bipyridinium molecules into the porous frameworks leads to the formation of 1D channel with positively charged surface, which shows high affinities to polar molecules such as methanol, ethanol, and water vapor. Additionally, the bipyridinium molecules possess conjugated pyridyl rings connected by carbon-carbon single bonds, which can rotate freely to keep twisted or large-conjugated planar configuration by controlling coordination condition during the self-assembly process. The cagelike pore space formed by these flexible bipyridinium molecules contains arene-arene stacked pyridyl rings and thus renders abundant π-π interaction sites for efficient adsorption of benzene and toluene molecules, and is also large enough to accommodate cyclohexane molecules. These metal-organic frameworks show efficient adsorption for benzene, toluene, and cyclohexane molecules through high utilization efficiency of unique pore space, and display rarely broad-spectrum adsorptivity to various organic pollutants with hydrophilic/hydrophobic, conjugated/nonconjugated characteristics. [ABSTRACT FROM AUTHOR]

This work constitutes a guide towards the preparation of metal-organic framework materials (MOF) supported and/or confined in activated carbon monoliths (ACM). The resulting hybrid porous materials exhibit improved physico-chemical properties as compared with their parent constituents. The different hybrids were obtained exploring several experimental approaches, which were thoroughly discussed. All hybrids were characterized by N 2 adsorption isotherms, SEM, TGA and XRD techniques. The characterization studies pointed out that the preparation conditions are of paramount importance in defining the nucleation and growth of HKUST-1, either outside of the carbon grains (surface coating), and/or in the internal pores (bulk confinement). While the surface coating was achieved by directly synthesizing the MOF in presence of the ACM (i.e. in-situ synthesis), bulk confinement is favored after applying an additional step that involves a pre-nucleation at low temperatures (5 °C). The hybrid material with the best performance, sample A5(1), shows enhanced mechanical properties compared to its parent counterparts, combined with high apparent surface area (up to 1300 m 2 /g), an improved crushing strength (about 8 times superior to ACM) and a geometrical density of around 0.45 cm 3 /g, which almost duplicates that of ACM. Last but not least, the adsorption behavior of the hybrid was tested for CO 2 and CH 4 adsorption. Application of IAST equation to the single component adsorption isotherms at room temperature gives rise to a CO 2 /CH 4 selectivity factor of 5.5 in the hybrid material, larger than that on ACM (S = 3.5). [ABSTRACT FROM AUTHOR]

Presented here is a new porous tetrahedral Zn(II)-tetrazolate framework, namely [Zn 2 (mtz) 3 (OH)] n ·n(DMF) ( 1 , Hmtz = 5-methyl-1H-tetrazole, DMF = N,N’-dimethylformamide), has been successfully synthesized under solvothermal conditions. Single crystal X-ray structural analysis reveals that compound 1 features a three-dimensional (3D) porous framework with 4-connected dia-type topology. The 1D channels along the crystallograhical c axis are occupied by the lattice DMF molecules. The desolvated samples show highly adsorption selectivity of CO 2 over N 2 . [ABSTRACT FROM AUTHOR]

A 3-D lanthanide metal–organic framework, [Tb2(L)1.5(DMF)2]·2DMF (1) (L = 14-diylbis(acylamino-21-diyl))-diisophthalic acid), has been synthesized under solvothermal conditions.1was characterized by X-ray single-crystal analysis and powder X-ray diffraction. The 3-D framework of1is constructed by 2-D channels embedded in a plane. Network analysis reveals that1is a (4,5,6,6)-connected net with stoichiometry (4-c)2(5-c)2(6-c)3. As expected, this terbium(III) metal–organic framework exhibits good properties for adsorbing organic dye molecules due to its NH- group. It shows good adsorption selectivity for rhodamine B (RB) rather than methyl orange (MO) and methylene blue (MB) molecules. [ABSTRACT FROM PUBLISHER]

Adsorptive removal of toxic compounds using advanced porous materials is one of the most attractive approaches. In recent years, the metal-organic frameworks (MOFs), a subset of advanced porous nano-structured materials, due to their unique characteristics are showing great promise for better adsorption/separation of various water contaminants. Given the importance of azo dye removal, as an important class of pollutants, this paper aims to review and summarize the recently published research on the effectiveness of various MOFs adsorbents under different physico-chemical process parameters in dyes adsorption. The effect of pH, the adsorption mechanism and the applicability of various adsorption kinetic and thermodynamic models are briefly discussed. Most of the results observed showed that the adsorption kinetic and isotherm of azo dyes onto the MOFs mostly followed the pseudo-second order and Langmuir models respectively. Also, the optimum pH value for the removal of majority of azo dyes by MOFs was observed to be in the range of ∼5–7. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs) are promising nanomaterials with unprecedented capacity to store small molecules. Despite this huge capacity, proposed methods for releasing these molecules are not yet feasible at a meaningful scale, largely because of the strong binding of the molecules and the thermally insulating nature of the adsorbent. It is likely that large amounts of energy would be required for operation at scale. Furthermore, the high adsorption capacity of MOFs is not typically matched by a high working capacity; adsorbed molecules are not readily retrieved. Here we show a series of magnetic framework composites (MFCs) synthesized from ferri-magnetic MgFe2O4 nanoparticles and the Zr-based MOF UiO-66 can be deployed in a magnetic induction swing adsorption process for CO2 capture and release. Exposure of the MFCs to an alternating current magnetic field resulted in the generation of heat by the embedded magnetic nanoparticle and fast release of CO2 from the MOF, with an unprecedented 100% of adsorbed CO2 released under a 42 mT field. This was achieved at a regeneration time of 240 s. The efficiency of the MISA process was shown to be dependent on the amount of MFC used, with efficiencies reaching 60% at just a gram scale. These local "nanoheaters" overcome the thermally insulating nature of the adsorbent, which has promising implications for use at scale. Additionally, the ability to access 100% of the adsorption capacity permits the use of strongly adsorbing, high-capacity MOFs that were previously discarded. [ABSTRACT FROM AUTHOR]

Originated from the pore space segmentation modification of a reported metal-organic framework (MOF) (NOTT-125), a new porous MOF ZnX was obtained and characterized by single-crystal X-ray diffraction, elemental analysis, X-ray powder diffraction and TGA. The ZnX exhibits remarkable selective CO adsorption property compared with that of the NOTT-125, which should be attributed to the enhanced gas-framework interactions induced by the fragmented pore space in ZnX. [ABSTRACT FROM AUTHOR]

Various articles have been written about MOFs, which are organic-inorganic polymer structures that are unique in three-dimensional porosity, crystalline structure, and their ability to adsorb cadmium ion pollutants from aqueous solutions. These materials possess active metal sites, highly porous structures, high specific surfaces, high chemical functionality, and porous topologies. It is necessary to study adsorption kinetics, isotherms, and mechanisms in order to better understand the adsorption process. Adsorption kinetics can provide information about the adsorption rate and reaction pathway of adsorbents. Adsorption isotherms analyze the possibility of absorbances based on the Gibbs equation and thermodynamic theories. Moreover, in practical applications, knowledge of the adsorption mechanism is essential for predicting adsorption reactions and designing MOFs structures. In this review, the latest suggested adsorption mechanisms, kinetics, and isotherms of MOFs-based materials for removing cadmium ions are presented. A comparison is then conducted between different MOFs and the mechanisms of cadmium ion removal. We also discuss the future role of MOFs in removing environmental contaminants. Lastly, we discuss the gap in research and limitations of MOFs as adsorbents in actual applications, and probable technology development for the development of cost-efficient and sustainable MOFs for metal ion removal. [ABSTRACT FROM AUTHOR]

Methane adsorption was studied in microporous materials with differences in their pore geometry and surface chemistry in order to evaluate the characteristics that enhance methane storage in porous materials. The studied materials included metal-organic frameworks (Cu-BTC, MIL-53 and ZIF-8), zeolites (5A and 13X) and an activated carbon (Maxsorb). Textural properties such as pore volume and specific surface area were studied by nitrogen adsorption–desorption isotherms. Methane adsorption was analyzed by means of measurements at low and high pressures (0–5000 kPa) at various temperatures (278–323 K). The effect of the adsorbate–adsorbent interaction was evaluated by the determination of the Henry constant using the adsorption data of methane at low pressures and 298 K. In addition, the isosteric enthalpy of adsorption using data of adsorption at several temperatures was obtained. A linear trend was observed between the Henry constant, the enthalpy of adsorption and the pore size, indicating that the latter is the most influential factor in the interaction of a microporous adsorbent and methane at room temperature. Also, it was found that the textural properties (i.e. specific surface and micropore volume) are directly related with the methane storage capacity at 298 K and 3.5 MPa. However, we obtained a deviation of this behavior for ZIF-8 that is related to its geometry and pore size. [ABSTRACT FROM AUTHOR]

The adsorption mechanism of ethane, ethylene, and acetylene (C2Hn; n = 2, 4, 6) on two microporous metal organic frameworks (MOFs) is described here that is consistent with observations from single crystal and powder X-ray diffraction, calorimetric measurements, and gas adsorption isotherm measurements. Two calcium-based MOFs, designated as SBMOF-1 and SBMOF-2 (SB: Stony Brook), form three-dimensional frameworks with one-dimensional open channels. As determined from single crystal diffraction experiments, channel geometries of both SBMOF-1 and SBMOF-2 provide multiple adsorption sites for hydrocarbon molecules through C-H···π and C-H···O interactions, similarly to interactions in the molecular and protein crystals. Both materials selectively adsorb C2 hydrocarbon gases over methane as determined with IAST and breakthrough calculations as well as experimental breakthrough measurements, with C2H6/CH4 selectivity as high as 74 in SBMOF-1. [ABSTRACT FROM AUTHOR]

Two three-dimensional (3D) porous heterometal-organic frameworks (HMOFs) with isostructures, [Zn2Cd(OH)(BTC)2(DMF)(H2O)2]·(H3O) (JUC-155A) and [ZnCo2(OH)(BTC)2(DMF)(H2O)2]·(H3O) (JUC-155B) (JUC=Jilin University China, BTC=1,3,5-benzenetricarboxylate and DMF= N, N-dimethylformamide), have been successfully synthesized by utilizing two kinds of 3d metal ions (Zn(II) and Cd(II) or Zn(II) and Co(II)) under conformable conditions. X-ray crystallography reveals that both HMOFs consist of trinuclear metal-carboxylate secondary building units (SBUs), and these SBUs are interlinked by the phenyl groups of BTC ligands to generate 3D open-frameworks with two types of channels of about 6.3 and 10.7 Å. Both HMOFs show the multifunctional properties in photoluminescence and adsorption. JUC-155B also exhibits an antiferromagnetic interaction, owing to the presence of dinuclear cobalt centers. Additionally, the high-pressure hydrogen storage of JUC-155A has been also examined at 77 K. By using mixed metal centers in clustered SBUs, it is a good strategy to construct those isostructures with heterometallic systems, and it is believed that the presence of such HMOFs will further facilitate the exploration of multifunctional materials. [ABSTRACT FROM AUTHOR]

Water pollution relating to human beings' health is a universal problem across community society. Highly efficient, economically feasible and easily achievable approaches are long-sought-after for water purification. Adsorption processes with porous materials ( e.g. zeolites, activated carbon, silica gel, metal-organic frameworks (MOFs)) have drawn much attention in this field during past decades. In it, MOFs with numerous active sites, uniform porosity and tailorable structure diversity are arising to be one of the most promising adsorbents for water purification. During the adsorption processes, influence factors that determine or affect the usability and performances of MOFs are mainly focused on the stability of MOFs, their affinity for contaminants and the conducting conditions (pH, initial concentration of the contaminants). In this review, we will systematically present the performances of MOFs (mainly focused on MOF crystals, MOF nanomaterial or MOF composites will be beyond the scope of this review) for contaminants purification (inorganic and organic contaminants) in water and give a detailed discussion about the connection among their performances, conducting condition factors and potential interaction mechanisms ( e.g. electrostatic interactions, coordination or p-p interaction). We hope this review will be beneficial to the design, regeneration and reuse of MOF adsorbents and promote the development of MOFs for water purification. [ABSTRACT FROM AUTHOR]

Two isostructural 3D metal-organic frameworks (MOFs), {[Zn3(tzba)3(dabco)] ·5DMF ·3H2O} ( 1) and {[Zn3(F-tzba)3(dabco)] ·5DMA ·3H2O} ( 2) [tzba = 4-(1 H-tetrazol-5-yl) benzolate, F-tzba = 2-fluoro-4-(1 H-tetrazol-5-yl) benzolate, dabco = triethylenediamine], were solvothermally synthesized from a tetrazolate-carboxylate bifunctional linker and a diamine ligand. The framework contains an uncommon metal-tetrazolate-carboxylate linear trinuclear Zn3(ttaz)3(COO)3 (ttaz = tetrazolyl) cluster, which serves as an eight-connected node to afford a 3D porous network. Both 1 and 2 show strong photoluminescence and selective luminescent quenching for Cu2+ ions and nitrobenzene relative to that shown by other metal ions (e.g., Na+, K+, Mg2+, Ca2+, Mn2+, Co2+, Ni2+, Cd2+, and Pb2+) and organic solvents (e.g., methanol, ethanol, acetonitrile, n-propanol, 2-propanol, ethyl acetate, toluene, dichloromethane, N, N′-dimethylformamide, and N-methylpyrrolidone). It is interesting to find that relative to 1, 2 decorated with F atoms exhibits more efficient luminescent sensing for these two guests. Furthermore, 2 also adsorbs more CO2 and has higher CO2/CH4 adsorption selectivities than 1 under the same conditions, which can be ascribed to the CO2-philic F sites in the pores of 2. These advantages make 2 a promising material in both luminescent sensors and CO2 separation from a CO2/CH4 mixture. [ABSTRACT FROM AUTHOR]

In our efforts toward the rational design and systematic synthesis of porous 3D MOFs, three 3D frameworks of Zn-MOFs ([Zn(BDC)(TIB)]·3H2O (Zn-MOF-1) (TIB = 1,3,5-tri(1H-imidazol-1-ly) benzene and H2BDC = 1,4-dicarboxybenzene), [Zn(BDA)(TIB)2/3]n (Zn-MOF-2) (H2BDA = 4,4′-biphenyl-dicarboxylic acid) and [Zn3(BDC)2(BDA)(TIB)2]n (Zn-MOF-3)) were successfully synthesized, based on different multicarboxylate ligands through solvothermal reactions. The resulting MOFs show similar 3D structures with different pore sizes which lead to distinct selective adsorption for organic dyes. Remarkably, Zn-MOF-1 exhibits an excellent capacity to adsorb CR (congo red) with high selectivity, and it maintains an almost identical adsorption performance after being recycled several times. [ABSTRACT FROM AUTHOR]

Interpenetrated metal-organic frameworks (MOFs) are often observed to show lower porosity than their non-interpenetrating analogues. It would be highly desirable if the interpenetrated MOFs could still provide high stability, high rigidity, and optimal pore size for applications. In this work, an asymmetrical tricarboxylate organic linker was rationally designed for the construction of a copper(II)-based microporous MOF with a twofold interpenetrated structure of Pt3O4 topology. In spite of having structural interpenetration, the activated MOF shows high porosity with a Brunauer-Emmett-Teller surface area of 2297 m2 g−1, and high CO2 (15.7 wt % at 273 K and 1 bar) and H2 uptake (1.64 wt % at 77 K and 1 bar). [ABSTRACT FROM AUTHOR]

Microporous materials with higher uptake – offtake difference per adsorption – desorption cycle have great potential to design adsorption assisted chillers, heat pumps and thermal batteries. In this context, we report a green reaction method for synthesizing aluminium fumarate (AlFum) metal-organic framework (MOF). The water uptake on AlFum shows S-shape isotherm curve with sharp increase in uptake – offtake difference in a narrow pressure range. The proposed green synthesized AlFum exhibits higher deliverable energy capacity as compared to that of conventional (dimethylformamide based synthesis) AlFum for adsorptive cooling applications. [ABSTRACT FROM AUTHOR]

We have achieved success in obtaining three novel two-dimensional porous metalloporphyrin frameworks (MPFs) through solvothermal reactions, by using 5,15-di(4-pyridyl)-10,20-bis(3,4,5-trifluorophenyl) porphyrin ( trans -Py 2 (F 3 -ph) 2 Por) metalated with Fe ( 1 ), Co ( 2 ), and Ni ( 3 ) salts respectively. TGA reveals that they all have high thermal stabilities. Gas adsorption studies indicate that three MPFs have relatively preferable H 2 uptake capacities and the selective adsorption of CO 2 over N 2 . [ABSTRACT FROM AUTHOR]

Competitive adsorption and selectivity of benzene and water vapor were studied on the microporous metal organic frameworks (HKUST-1). The adsorption equilibrium and kinetics of pure component as well as binary mixtures of benzene and water vapor were systematically investigated on the HKUST-1. Their binary adsorption selectivity and permeation selectivity are predicted via the IAST method. Results showed that the equilibrium data of benzene and water vapor depicted the Langmuir–Freundlich and Dual Site Langmuir–Freundlich (DSLF) type adsorption isotherms, respectively. Benzene exhibited much higher isosteric heat and desorption activation energy than water vapor, indicating a stronger interaction with the HKUST-1. The adsorption selectivity of benzene/water on the HKUST-1 was of about ∼8.32 at 318 K and 1.0 mbar, and its diffusivity selectivity was about 17.6 at 298 K and 1.5 mbar, respectively. Breakthrough curves of benzene showed a remaining capacity of about 94.7% and 72.9% in the presence of 13 and 34 RH%. Thus, the HKUST-1 is more selective or preferential adsorption for benzene molecules in comparison to water molecules at high temperature and low pressure. Also, it shows the advantage of kinetic separation for VOCs and water vapor. [ABSTRACT FROM AUTHOR]

In this work, we report on the controlled growth of trivalent metal-organic frameworks, MIL-53(Al), via an acid-assisted hydrothermal method. We demonstrated that some coordination modulation such as hydrochloric acid and acetic acid, could offer hydrogen ions or extra charge as well as competitive organic linkers during the hydrothermal synthesis, which was beneficial for improving crystal quality, controlling crystal morphology and increasing surface areas of the metal-organic frameworks. In addition, the use of additive acids also enhanced the product yields and thermal stability of the frameworks. The synthesized high-specific-surface MIL-53(Al) displayed strong CO2-adsorption capacity, indicating their potential applications as valuable adsorbent for low-concentration CO2 capture. [ABSTRACT FROM AUTHOR]