Range Of Molar Ratios Research Articles

Improved Stabilities of Immobilized Glucoamylase on Functionalized Mesoporous Silica Synthesised using Decane as Swelling Agent

Ordered mesoporous silica, with high porosity was used to immobilize glucoamylase via adsorption and covalent binding. Immobilization of glucoamylase within mesoporous silica was successfully achieved, resulting in catalytically high efficiency during starch hydrolysis. In this study, mesoporous silica was functionalized by co-condensation of tetraethoxysilane (TEOS) with organosilane (3-aminopropyl) triethoxysilane (APTES) in a wide range of molar ratios of APTES: TEOS in the presence of triblock copolymer P123 under acidic hydrothermal conditions. The prepared materials were characterized by Small angle XRD, Nitrogen adsorption – desorption and 29Si MAS solid state NMR. N2 desorption studies showed that pore size distribution decreases due to pore blockage after functionalization and enzyme immobilization. Small angle XRD and 29Si MAS NMR study reveals mesophase formation and Si environment of the materials. The main aim of our work was to study the catalytical activity, effect of pH, temperature storage stability and reusability of covalently bound glucoamylase on mesoporous silica support. The result shows that the stability of enzyme can be enhanced by immobilization. © 2013 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0)

Preparation of Fe-Mn/K/Al2O3 Fischer-Tropsch Catalyst and Its Catalytic Kinetics for the Hydrogenation of Carbon Monoxide

A K promoted iron-manganese catalyst was prepared by sol-gel method, and subsequently was tested for hydrogenation of carbon monoxide to light olefins. The kinetic experiments on a well-characterized Fe-Mn/K/Al2O3 catalyst were performed in a fixed-bed micro-reactor in a temperature range of 280-380 °C, pressure range of 0.1-1.2 MPa, H2/CO feed molar ratio range of 1-2.1 and a space velocity range of 2000-7200 h−1. Considering the mechanism of the process and Langmuir-Hinshelwood-Hogan-Watson (LHHW) approach, unassisted CO dissociation and H-assisted CO dissociation mechanisms were defined. The best models were obtained using non-linear regression analysis and Levenberg-Marquardt algorithm. Consequently, 4 models were considered as the preferred models based on the carbide mechanism. Finally, a model was proposed as a best model that assumed the following kinetically relevant steps in the iron-Fischer-Tropsch (FT) synthesis: (1) CO dissociation occurred without hydrogen interaction and was not a rate-limiting step; (2) the first hydrogen addition to surface carbon was the rate-determining steps. The activation energy and adsorption enthalpy were calculated 40.0 and −30.2 kJ·mol−1, respectively.

Comprehensive picture ofp-type doping of P3HT with the molecular acceptor F4TCNQ

By means of optical spectroscopy, Kelvin probe, and conductivity measurements, we study the $p$-type doping of the donor polymer poly(3-hexylthiophene), P3HT, with the molecular acceptor tetrafluorotetracyanoquinodimethane, F${}_{4}$TCNQ, covering a broad range of molar doping ratios from the ppm to the percent regime. Thorough quantitative analysis of the specific near-infrared absorption bands of ionized F${}_{4}$TCNQ reveals that almost every F${}_{4}$TCNQ dopant undergoes integer charge transfer with a P3HT site. However, only about 5$%$ of these charge carrier pairs are found to dissociate and contribute a free hole for electrical conduction. The nonlinear behavior of the conductivity on doping ratio is rationalized by a numerical mobility model that accounts for the broadening of the energetic distribution of transport sites by the Coulomb potentials of ionized F${}_{4}$TCNQ dopants.

Soot Formation in Propane/Air Diffusion Flames

Soot formation and growth in propane/air diffusion flames in a wide range of mole ratio of propane to air from 0.01 to 0.1 have been studied experimentally and theoretically. The concentration of acetylene, soot yield and particle size have been measured and the growth of soot particle has been simulated from surface growth and nucleation processes. The rate coefficient of surface growth has been correlated with the mole ratio of propane to air and the comparisons of particle size between measured and calculated results have been made.

Corneal Stromal Cell Growth on Gelatin/Chondroitin Sulfate Scaffolds Modified at Different NHS/EDC Molar Ratios

A nanoscale modification strategy that can incorporate chondroitin sulfate (CS) into the cross-linked porous gelatin materials has previously been proposed to give superior performance for designed corneal keratocyte scaffolds. The purpose of this work was to further investigate the influence of carbodiimide chemistry on the characteristics and biofunctionalities of gelatin/CS scaffolds treated with varying N-hydroxysuccinimide (NHS)/1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide hydrochloride (EDC) molar ratios (0–1) at a constant EDC concentration of 10 mM. Results of Fourier transform infrared spectroscopy and dimethylmethylene blue assays consistently indicated that when the NHS to EDC molar ratio exceeds a critical level (i.e., 0.5), the efficiency of carbodiimide-mediated biomaterial modification is significantly reduced. With the optimum NHS/EDC molar ratio of 0.5, chemical treatment could achieve relatively high CS content in the gelatin scaffolds, thereby enhancing the water content, glucose permeation, and fibronectin adsorption. Live/Dead assays and interleukin-6 mRNA expression analyses demonstrated that all the test samples have good cytocompatibility without causing toxicity and inflammation. In the molar ratio range of NHS to EDC from 0 to 0.5, the cell adhesion ratio and proliferation activity on the chemically modified samples significantly increased, which is attributed to the increasing CS content. Additionally, the materials with highest CS content (0.143 ± 0.007 nmol/10 mg scaffold) showed the greatest stimulatory effect on the biosynthetic activity of cultivated keratocytes. These findings suggest that a positive correlation is noticed between the NHS to EDC molar ratio and the CS content in the biopolymer matrices, thereby greatly affecting the corneal stromal cell growth.

Effects of Polyunsaturated Acyl Chains on Coexisting Liquid Ordered/Liquid Disordered Phases

Ternary mixtures of POPC, sphingomyelin (SM) and cholesterol (Chol) form coexisting liquid ordered and liquid disordered fluid phases over a wide range of molar ratios. We examined the effects of polyunsaturated acyl chains in this ternary system by incrementally exchanging SDPC (18:0,22:6 PC) for POPC. All measurements were performed on extruded LUVs formed above the main phase transition of the SM. Changes in bilayer properties of the two phases were monitored with NBD linked to di-16:0 PE, which partitions into the liquid ordered phase, and NBD linked to di-18:1 PE which partitions into the liquid disordered phase. Fluorescence lifetime and anisotropy decay dynamics of both fluorescent probes were assessed via frequency-domain measurements collected from 5 to 300 MHz. In both phases the exchange of SDPC for POPC reduced the average fluorescence lifetime of the two probes from the value observed in 1/1/1 POPC/SM/chol. In both phases the lifetime was reduced to a value similar to that observed in a ternary mixture consisting of 8/1/1 POPC/SM/chol. In the liquid disordered phase the addition of SDPC had essentially no influence on probe dynamics, while in the liquid ordered phase SDPC caused a significant acceleration of probe rotational motion. This result was unexpected since it was assumed that the SDPC would be present only in the liquid disordered phase. FRET measurements using di-16:0-PE labeled with NBD and di-18:1 PE labeled with rhodamine were performed in order to monitor changes possible changes in domain size induced by the exchange of POPC for SDPC. Initial results show similar transfer efficiency between these two probes in 1/1/1 POPC/SM/chol and in 1/2/3/3 POPC/SDPC/SM/chol, suggesting the presence of SDPC does not greatly perturb domain size and structure.

Effect of variation Mn/W molar ratios on phase composition, morphology and optical properties of MnWO4

Manganese tungstate (MnWO4) particles were successfully synthesized by a microwave hydrothermal method using MnCl2·4H2O and Na2WO4·2H2O as the starting materials. The products were characterized by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy and UV–vis absorption spectra. Results show that pure MnWO4 particles can be fabricated in the Mn/W molar ratio range from 1:2 to 2:1. The crystallinity of MnWO4 increases first and then decreases with increasing Mn/W molar ratio. MnWO4 morphology transforms from nanorods to aggregated spheres. UV–vis absorption spectra of these two morphologies exhibit a distinct redshift compared with bulk MnWO4. The band gaps of the nanorods and aggregated spheres-like MnWO4 particles are 2.75 eV and 2.65 eV, respectively.

Design of inorganic polymer cements: Effects of matrix strengthening on microstructure

The effects of bulk composition and microstructure on strengthening mechanisms and fracture resistance were investigated for metakaolin based geopolymers. Crack initiation and propagation under mechanical and environmental stresses were correlated to pore size distribution and bulk composition. Based on IR spectra and porosity analysis, it was observed that capillary pores and the nature of alkali-aluminosilicate hydrated named polysialates (H–M–A–S) determine cracks initiation site in the Al-rich geopolymer samples with low Si/Al molar ratio (range 1.23–1.5). These samples exhibited low flexural strength, Young modulus and Impact toughness as well as delayed failure under environmental stresses. Increasing the Si/Al molar ratio (range 1.79–2.42) improved the flexural strength and Impact toughness. Formation of more polymerized H–M–A–S phases contributed to strengthening the matrices and hinder axial cracks; consequence of toughening mechanisms developed by the coarsening on molecular scale of H–M–A–S.

Interaction of Nonionic Surfactants and Hydrophilic Ionic Liquids in Aqueous Solutions: Can Short Ionic Liquids Be More Than a Solvent?

The interaction between an ethoxylated nonionic surfactant (C(12-14)EO(8)) and three conventional hydrophilic imidazolium-based ionic liquids (bmim-octyl SO(4), bmim-methyl SO(4), and bmim-BF(4)) in aqueous solution has been investigated. In most of the reported studies where a surfactant is dissolved in an ionic liquid aqueous solution, conventional ionic liquids are merely considered to be solvents. Consequently, the resulting critical micelle concentration (cmc) is considered to be that of the surfactant. However, given that the three ionic liquids selected showed the typical shape of a surface-active compound when the surface tension was plotted against concentration, the role of these compounds as secondary surfactants and consequently the possibility of mixed-micelle formation have been investigated. Different series of experiments where a surfactant and an ionic liquid were combined in a wide range of mole ratios have been performed and treated as typical binary surfactant systems in aqueous solution. It has been found for the three surfactant/ionic liquid systems that depending on the surfactant mole fraction, α(1), attractive or repulsive interactions in mixed-micelle formation are produced. Therefore, when we select the appropriate α(1) these systems can be adjusted to a given application, depending on whether monomers or micelles are mainly required.

Formation of Ethylene–Silica Nanofibers with Concentric Circular Mesopores Inside and Lamellar Mesopores on the Surfaces

Ethylene-silica nanofibers with concentric circular mesopores inside and lamellar mesopores outside were prepared using stearyltrimethylammonium bromide (STAB) as template and (S)-beta-citronellol as a co-structure-directing agent. They were formed at the (S)-beta-citronellol/STAB molar ratio range of 3:1 to 4:1. Field emission scanning electron microscopy and transmission electron microscopy images taken after different reaction times revealed a phase transition from hexagonal to lamellar phase on the surface of the organic-inorganic hybrid silica nanofibers. The nanofibers with concentric circular pore channels were proposed to be formed from spherical micelles. With increasing the (S)-beta-citronellol/STAB molar ratio from 0.5:1 to 5:1, the morphology changed from short hexagonal rod to long nanofiber, and then to shrunk multilamellar vesicle. Moreover, 1,4-phenylene-silica nanofibers and nanoparticles with concentric circular mesopores inside and lamellar mesopores outside were also prepared.

Mechano-chemical synthesis of manganese borohydride (Mn(BH4)2) and inverse cubic spinel (Li2MnCl4) in the (nLiBH4 + MnCl2) (n = 1, 2, 3, 5, 9 and 23) mixtures and their dehydrogenation behavior

Manganese borohydride (Mn(BH4)2) was successfully synthesized by a mechano-chemical activation synthesis (MCAS) from lithium borohydride (LiBH4) and manganese chloride (MnCl2) by applying high energy ball milling for 30 min. For the first time a wide range of molar ratios n = 1, 2, 3, 5, 9 and 23 in the (nLiBH4 + MnCl2) mixture was investigated. During ball milling for 30 min the mixtures release only a very small quantity of H2 that increases with the molar ratio n but does not exceed ∼0.2 wt.% for n = 23. However, longer milling duration leads to more H2 released. For the equimolar ratio n = 1 the principal phases synthesized are Li2MnCl4, an inverse cubic spinel phase, and the Mn(BH4)2 borohydride. For n = 2 a LiCl salt is formed which coexists with Mn(BH4)2. With the n increasing from 3 to 23 LiBH4 is not completely reacted and its increasing amount is retained in the microstructure coexisting with LiCl and Mn(BH4)2. Gas mass spectrometry during Temperature Programmed Desorption (TPD) up to 450 °C shows the release of hydrogen as a principal gas with a maximum intensity around 130–150 °C accompanied by a miniscule quantity of borane B2H6. The intensity of the B2H6 peak is 200–600 times smaller than the intensity of the corresponding H2 peak. In situ heating experiments using a continuous monitoring during heating show no evidence of melting of Mn(BH4)2 up to about 270–280 °C. At 100 °C under 1 bar H2 pressure the ball milled n = 2 and 3 mixtures are capable of desorbing quite rapidly ∼4 wt.% H2 which is a very large amount of H2 considering that the mixture also contains 2 mol of LiCl salt. The H2 quantities experimentally desorbed at 100 and 200 °C do not exceed the maximum theoretical quantities of H2 expected to be desorbed from Mn(BH4)2 for various molar ratios n. It clearly confirms that the contribution from B2H6 evolved is negligibly small (if any) when desorption occurs isothermally in the practical temperature range 100–200 °C. It is found that the ball milled mixture with the molar ratio n = 3 exhibits the highest rate constant k and the lowest apparent activation energy for dehydrogenation, EA ∼ 102 kJ/mol. Decreasing or increasing the molar ratio n below or above 3 increases the apparent activation energy. Ball milled mixtures with the molar ratio n = 2 and 3 discharge slowly H2 during storage at room temperature and 40 °C. The addition of 5 wt.% nano-Ni with a specific surface area of 60.5 m2/g substantially enhances the rate of discharge at 40 °C.

The DNA–DNA spacing in gemini surfactants–DOPE–DNA complexes

Gemini surfactants from the homologous series of alkane-α,ω-diyl-bis(dodecyldimethylammonium bromide) (CnCS12, number of spacer carbons n=2–12) and dioleoylphosphatidylethanolamine (DOPE) were used for cationic liposome (CL) preparation. CLs condense highly polymerized DNA creating complexes. Small-angle X-ray diffraction identified them as condensed lamellar phase LαC in the studied range of molar ratios CnGS12/DOPE in the temperature range 20–60°C. The DNA–DNA distance (dDNA) is studied in dependence to CnGS12 spacer length and membrane surface charge density. The high membrane surface charge densities (CnGS12/DOPE=0.35 and 0.4mol/mol) lead to the linear dependence of dDNA vs. n correlating with the interfacial area of the CnGS12 molecule.

Investigation of the interactions of lupane type pentacyclic triterpenes with outer leaflet membrane phospholipids – Langmuir monolayer and synchrotron X-ray scattering study

Lupane type pentacyclic triterpenes (LTs) are pharmacologically active natural products isolated from different plants. They have broad spectrum of therapeutic action ranging from anticancer via anti-HIV, antibiotic to anti-inflammatory and anti-protozoal activity. Many scientific papers underline that the key stage in the LT mechanism of action is their incorporation into cellular membrane and the interaction with the structural lipids. In our research we apply Langmuir monolayers as a versatile platform for the investigation of these phenomena, since till now important aspects concerning this issue are incomprehensible. We focus our attention on the interactions of lupeol and betulinic acid with choline-headgroup structural lipids: a representative of saturated glycerophosphatidylcholines (DPPCs), and octadecyl-sphingomyelin, a representative of membrane sphingolipids. Application of complementary physicochemical techniques such as the Langmuir technique, Brewster angle microscopy, and grazing incidence X-ray diffraction supported by thermodynamic analysis enabled us to investigate the intermolecular interactions in such binary model systems. Our results corroborate that LT is miscible with the outer leaflet membrane phospholipids, both DPPC and SM in the whole range of mole ratios. Moreover, the introduction of LT into the phospholipid film, even in small proportion, leads to the loss of periodical ordering of the phospholipid molecules and the disappearance of the diffraction signal as observed by GIXD. Our results also proved that LT does not form any surface complexes of fixed stoichiometry resembling the well characterized lipid rafts.

Enhancement of p-type thermoelectric properties in an Mg2Sn system

In order to investigate the effect of both composition and the Ag-doping on the thermoelectric properties of Mg2Sn, samples with molar-ratio (Mg:Sn) range from 65:35 to 71:29 were synthesized using a vacuum melting process. For undoped specimens all the samples showed p-type characteristics at room temperature. As the temperature was increased, the Seebeck coefficients of all the samples were converted into n-type. The transition of the Seebeck coefficient from p- to n-type starts at lower temperatures for Mg-excess compositions than for Sn-excess compositions. Ag atoms were doped into the Mg2Sn in order to retain the p-type thermoelectric properties at high temperatures. The microstructures, as well as the thermoelectric properties, were also investigated. As a result, Ag-doping brought about a p-type power factor much higher than that for an undoped sample, especially for Sn-excess Mg2Sn compositions. The highest value of the figure of merit (0.18) was obtained from a 3-mol%Ag-doped Mg2Sn at 600 K, which resulted from the increase in the power factor and the decrease in lattice thermal conductivity.

On the improved absorption of carbon monoxide in the ionic liquid 1-hexyl-3-methylimidazolium chlorocuprate

This study is focused on the design of a liquid phase system to be used in facilitated transport-supported ionic liquid membranes (SILMs) for the recovery of carbon monoxide from gaseous streams based on the ability of CO molecules to form π complexation bounds with Cu+ ion. As liquid phase we propose the use of the ionic liquid 1-hexyl-3-methyl-imidazolium chlorocuprate prepared by the direct mixture of copper(I) chloride (CuCl) with 1-hexyl-3-methylimidazolium chloride ([hmim][Cl]).A comprehensive look at the reaction mechanism and the equilibrium parameters obtained from the experimental characterization of the physical and chemical solubility of carbon monoxide in pure [hmim][Cl], and in mixtures CuCl/[hmim][Cl] is presented. The gas equilibrium solubility experimental work was carried out in the CuCl/[hmim][Cl] molar ratio range from 0 to 0.75, temperature from 273.15 to 303.15K and pressures up to 20bar. The values of the Henry’s law constant for the physical solubility of CO in [hmim][Cl] changed from 15.3×10−3 to 2.7×10−3molkg−1bar−1 as the temperature increased from 273.15 to 293.15K. The chemical solubility of CO in the reactive ionic liquid media increased with the increase of the concentration of CuCl, with the increase of pressure and as temperature decreases. In the operation range of variables the maximum absorption of CO was of 2.26molkg−1 that was reached working at 20bar, at CuCl/[hmim][Cl] molar ratio of 0.75 and 273.15K.

The microstructure of DNA-egg yolk phosphatidylcholine-gemini surfactants complexes: effect of the spacer length

The length of spacer of gemini surfactants affects the DNA packing in DNA-neutral phospholipid-gemini surfactant complexes. The microstructure of complexes DNA-egg yolk phosphatidylcholine (EYPC)-alkane-α,ω-diyl-bis(dodecyl­dimethylammonium bromides) (CnGS, spacer n=2-12, n is even) was studied using small angle X-ray diffraction. At EYPC:CnGS=1:1 mol/mol, the condensed lamellar phase was identified in complexes with CnGS, n=2-4, whereas longer spacer (n≥6) induced a hexagonal phase. The condensed lamellar phase Lαc was observed in the range 2\≤ EYPC:GnGS≤10 (mol/mol) in all complexes. The distance between adjacent DNA strands increases linearly with decreasing surface charge density of EYPC-CnGS vesicles. We determined the increase in dDNA 0.40±0.03 nm/1 mol of EYPC from the slope of dDNA=f (molEYPC/molCnGS) in the range of molar ratios 2≤EYPC:CnGS≤5. At lower surface charge density, EYPC:CnGS>5 mol/mol, the length of CnGS spacer (n=6-10) modulates the DNA-DNA distance. Both the short spacer of CnGS and the low molar ratio EYPC:CnGS result in the closest DNA-DNA packing. A high surface charge density of membrane was reported as a key parameter for transfection efficiency of Lαc phase-forming complexes.

Synthesis and Microwave Absorption Properties of Magnetite Nanoparticles

Nanoparticles of Fe3O4 with various sizes were synthesized from FeCl3 x 6H2O, FeCl2 x 4H2O and NaOH by coprecipitation process. The crystal structure, morphology, particle size and magnetic property of the products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). It was found that the molar ratio of ferrous to ferric played an important role in the formation of Fe3O4 nanoparticles. The particle mean diameter swelled from approximately 10 to approximately 20 nm with the molar ratio range from 1:2 to 6:1. The saturation magnetization and the coercivity increased correspondingly. The complex permittivity epsilon(r) and permeability mu(r) of the Fe3O4 mixture with paraffin were measured using vector network analysis. Values of epsilon(r), and mu(r) were used to determine the reflection loss at various sample thicknesses, based on a model of microwave absorbing layer backed by a metal plate. The minimal reflection loss or the dip shifts to a lower frequency region with increasing thickness. When the thickness is 5 mm, the minimal reflection loss of Fe3O4 synthesized with the molar ratio of 6:1 and paraffin wax composites reaches -35.1 dB at 5.2 GHz and -30.2 dB at 17.6 GHz, respectively. The minimal reflection loss is attributed to the thickness of the absorber approximates an odd number multiple of a quarter of the propagation wavelength.

N-Propyl Propionate Synthesis via Catalytic Distillation - Experimental Investigation in Pilot-Scale

Catalytic distillation experiments were designed and carried out in a pilot-scale column to prove the technical feasibility of the heterogeneously catalyzed n-propyl propionate synthesis by esterification of propionic acid with 1-propanol using the surface-sulfonated ion-exchange resin Amberlyst 46. The experiments cover a broad range of decisive operational parameters, for example, reflux ratio, column load, distillate-to-feed ratio, and molar feed ratio of the reactants. The reconciled results comprise a complete set of concentration and temperature profiles along the column height and, hence, exhibit detailed and reliable data for model validation purposes.

Towards efficient polyoxometalate encapsulation in MIL-100(Cr): influence of synthesis conditions

The one-pot encapsulation of phosphotungstic acid in the metal–organic framework MIL-100(Cr) has been studied under different synthesis conditions. Both conventional and microwave heating methods have been explored for three different solvent systems: pure aqueous or organic (DMF) phase and biphasic mixtures (water/2-pentanol). Biphasic systems yielded crystals with similar textural properties as those formed in water. The use of DMF as solvent promotes the formation of gel-like solids with dual porosity and enhanced accessibility. The addition of phosphotungstic acid (PTA, H3PW12O40.xH2O) to the MIL-100(Cr) synthesis mixture results in its direct encapsulation. 31P MAS NMR, elemental analysis, N2 adsorption and FT-IR spectroscopy confirm the incorporation of PTA in the sample. The highest PTA encapsulation loading (30 wt%) was obtained by synthesis with microwave heating in biphasic solvent systems (W/Cr molar ratio range between 0.5 and 0.25). Microwave irradiation decreases the time of synthesis (from 4 days to 3 hours) while the use of biphasic media preserves the PTA integrity without affecting the formation of the MOF. The interaction of PTA with the MIL-100(Cr) structure results in some loss of the Lewis acidity, while the Bronsted acidity is hardly affected.

One-Pot Synthesis and CO2 Adsorption Properties of Ordered Mesoporous SBA-15 Materials Functionalized with APTMS

Amino-functionalized SBA-15 materials were synthesized by cocondensation of tetraethoxysilane (TEOS) with organosilane aminopropyltrimethoxysilane (APTMS) in a wide range of molar ratios of APTMS to TEOS in the presence of triblock copolymer P123 under acidic synthesis conditions. The effects of F– periodically added into the synthesis solution and of the APTMS concentration in the initial synthesis solution on the textural properties of the functionalized SBA-15 were investigated in detail. The addition of APTMS into the initial synthesis solution can adversely affect the SBA-15 mesostructure, whereas the ordered mesostructure of the amino-functionalized SBA-15 materials can be reserved by the introduction of F– into the synthesis solution. The results from the adsorption of CO2 on the synthesized materials show that the mesoporous SBA-15 functionalized with a high concentration of APTMS in the initial synthesis solution in the presence of F– could be a potential adsorbent for CO2 capture and separation.