Isosteric Enthalpy Of Adsorption Research Articles

Synthesis of biomass combustion fly ash derived zeolites for CO2 adsorption: Optimisation of hydrothermal synthetic pathway

Industrial biomass combustion fly ash has been investigated as a precursor for zeolites with a view to evaluate the potential for adsorption of CO2. The synthesis methodology has been optimised via Design of Experiment by employing a Taguchi L9 array. Three variables were identified as statistically significant, the crystallisation temperature, crystallisation time and the liquid to solid ratio. Analysis of the main effects revealed an optimum set of conditions which produced a sample with the highest adsorption capacity of those prepared, 1.84 mmol g−1 at 50 °C. This was a result of the conversion of the as-received fly ash into type A (LTA) and type X (FAU) zeolites after alkaline fusion with NaOH and hydrothermal treatment. The enthalpy of adsorption was estimated at -40.2kJmol−1 and was shown to be dependent on surface coverage; the isosteric enthalpy of adsorption at zero coverage was -86 kJ mol−1. The working capacity of the adsorbent was maintained at 85 % of the first adsorption uptake after a total of 40 cycles in a simulated temperature swing adsorption process (50 °C/150 °C adsorption/desorption). The equilibrium and kinetic CO2 adsorption isotherms are presented and modelled through non-linear regression to reveal the adsorption mechanisms demonstrated by the fly ash-derived zeolites. Significant heterogeneity exists within the multi-phase zeolite which presents both micro and mesoporosity. The developed adsorbent presents a feasible route to valorisation of biomass combustion fly ash with good potential for application in the separation of CO2.

From fundamental materials chemistry to sensing applications: Unravelling the water adsorption mechanism of a luminescent optical fibre sensor membrane

This work provides insight into the correlation between the luminescent response of a water-vapour optical fibre sensor and the textural properties of its lanthanide-doped silica coating. To this end, a library of 16 silica xerogels derived from combinations between 2 lanthanide dopants (EuIII, TbIII) and 8 antenna ligands was synthesised and characterised by photoluminescence spectroscopy and N2 and CO2 adsorption-desorption isotherms, among others. Based on the best luminescent response and most-suited porous texture, the material doped with TbIII and 2,2′-(4-(2-Ethoxyethoxy)pyridine-2,6-diyl)bis(4,5-dihydrooxazole) was selected to construct the probe. A film of this material was affixed to a commercial silica fibre by dip-coating and the resulting sensor was tested in a climatic chamber with relative humidity ranging from 20 to 90% to obtain normalised time-response and calibration curves at three temperatures. The response was linear up to certain water-vapour concentrations, beyond which abruptly changed to polynomial, acting against the sensor resolution. The adsorption mechanism was elucidated by comparing the isosteric enthalpies of adsorption calculated from the sensor calibration curves to those determined from the monolith water-vapour isotherms, revealing that capillary condensation in the membrane mesopores was the key phenomenon leading to the response deviating from linearity.

Nitrogen-enriched flexible metal-organic framework for CO2 adsorption.

A novel MOF named [Zn2(L)(DMF)] was synthesized using solvothermal methods from the reaction of the new linker (4,4',4''-(4,4',4''-(benzene-1,3,5-triyltris(methylene))tris(3,5-dimethyl-1H-pyrazole-4,1-diyl))tribenzoic acid) and Zn(NO3)2·6H2O. This new MOF was characterized by means of different techniques: powder X-ray diffraction, N2 adsorption and desorption isotherms, thermogravimetric analysis, and scanning electron microscopy. Furthermore, suitable crystals were obtained, which allowed us to perform the X-Ray structure determination of this MOF. The capability of these new MOF to adsorb CO2 at different temperatures was measured and its isosteric enthalpy of adsorption was calculated. The novel MOF shows an uncommon node composed of a Zn3(-COO)6(DMF)2, and the asymmetric unit contains one crystallographically independent linker, one DMF molecule, and two Zn atoms. The [Zn2(L)(DMF)] MOF is a microporous material with high crystallinity and stability up to 250 °C. The multiple nitrogenated pyrazole linkers in its framework enhance its CO2 adsorption capabilities. This material exhibits a low CO2 isosteric enthalpy of adsorption (Hads), comparable to previously reported values for similar nitrogenated materials. All the observed CO2 adsorption capacities were further supported by DFT calculations.

Post-treatment strategies for pyrophoric KOH-activated carbon nanofibres.

The effect of two atmospheric post-treatment conditions directly after the KOH activation of polyacrylonitrile-based nanofibres is studied in this work. As post-treatment different N2 : O2 flow conditions, namely high O2-flow and low O2-flow, are applied and their impact on occurring reactions and carbon nanofibres' properties is studied by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), Raman spectroscopy, elemental analysis and CO2 and Ar gas adsorption. At high O2-flow conditions a pyrophoric effect was observed on the KOH-activated carbon nanofibers. Based on the obtained results from the TGA and DSC the pyrophoric effect is attributed to the oxidation reactions of metallic potassium formed during the KOH activation process and a consequent carbon combustion reaction. Suppression of this pyrophoric effect is achieved using the low O2-flow conditions due to a lower heat formation of the potassium oxidation and the absence of carbon combustion. Compared to the high O2-flow samples no partial destruction of the carbon nanofibers is observed in the SEM images. The determination of the adsorption isotherms, the surface area, the pore size distribution and the isosteric enthalpies of adsorption show the superior properties under low O2-flow conditions. The present micropore volume is increased from 0.424 cm3 g-1 at high O2-flow to 0.806 cm3 g-1 for low O2-flow samples, resulting in an increase of CO2 adsorption capacity of 38% up to 6.6 mmol g-1 at 1 bar. This significant improvement clearly points out the importance of considering highly exothermic potassium oxidation reactions and possible post-treatment strategies when applying KOH activation to electrospun carbon nanofiber materials.

Calculation and Comparison of Adsorption Curves of Three ISO-Variables A CSE Study of Lean Coal from China

A series of isothermal adsorption experimental data of MZQ coal sample in Shanxi province of China has been transformed to fit a temperature pressure-adsorption equation with high accuracy. Besides isothermal adsorption curve, isobaric adsorption curve and isosteric adsorption curve have been created and presented. The Clausius-Clapeyron equations have been used to illustrate that gas isosteric adsorption is an exothermic process. The calculation procedure of unit isosteric adsorption enthalpy has been present. The increase of adsorption amount causes the unit isosteric adsorption enthalpy exponentially decreased, so the unit isosteric desorption enthalpy exponentially decreased.

A Route to Understanding the Ethane Adsorption Selectivity of the Zeolitic Imidazolate Framework-8 in Ethane-Ethylene Mixtures.

Ethylene production has a negative environmental impact, with its separation step being one of the major contributors of pollution. This has encouraged the search for energy-efficient alternatives, among which the adsorptive separation of ethane and ethylene stands out. ZIF-8 is a molecular sieve that is potentially useful for this purpose. It is selective to ethane, an exceptional property that remains unexplained. Furthermore, the adsorption of ethane and ethylene above room temperature, such as at steam cracking process outlet temperatures, has not been addressed either. This work aims to fill this knowledge gap by combining experiments at very low volumetric fillings with density-functional theory modelling methods. Adsorption isotherms of ethane and ethylene on ZIF-8 at pressures below 0.3 bar and 311 K, 333 K, and 363 K were measured using zero-length column chromatography. The low-pressure domain of the isotherms contains information on the interactions between the adsorbate molecules and the adsorbent. This favors the understanding of their macroscopic behavior from simulations at the atomic level. The isosteric enthalpy of adsorption of ethane remained constant at approximately -10 kJ/mol. In contrast, the isosteric enthalpy of adsorption of ethylene decreased from -4 kJ/mol to values akin to those of ethane as temperature increased. ZIF-8 selectivity to ethane, estimated from ideal adsorbed solution theory, decreased from 2.8 to 2.0 with increasing pressure up to 0.19 bar. Quantum mechanical modelling suggested that ethylene had minimal interactions with ZIF-8, while ethane formed hydrogen bonds with nitrogen atoms within its structure. The findings of this research are a platform for designing new systems for the adsorptive separation of ethane and ethylene and thus, reducing the environmental impact of ethylene production.

CO2 Adsorption on Natural Zeolites from Puebla, México, by Inverse Gas Chromatography

The applicability of clinoptilolite zeolites in controlling the emission of greenhouse gases (GHGs) such as CO2, the most significant GHG, is investigated herein. In this research, Mexican natural zeolites (ATN) originating from an Atzinco deposit in the state of Puebla were used. Samples of modified clinoptilolite (ATH4, ATH3, ATH2 and ATH1) were obtained from the starting material by acid treatment of various intensities. Inverse gas chromatography was used to evaluate CO2 adsorption in clinoptilolite, natural and chemically modified. Adsorption of CO2 was investigated in the temperature range of 433–573 K, using a TCD detector, and He as a carrier gas. The experimental CO2 adsorption data were processed by Freundlich and Langmuir equations. The degree of interaction between CO2 and the dealuminated clinoptilolite samples was examined through the evaluation of the isosteric enthalpy of adsorption. This calculation was made by using the Clausius–Clapeyron equation, which established the following sequence: ATH1 > ATH2 > ATH4 > ATN > ATH3. The nanoporosity of these clinoptolite zeolites from new deposit in sedimentary rocks was studied through HRADS adsorption of N2. Simultaneously, these zeolites were, respectively, characterized by XRD, EDS, and SEM. Micropores are described by the Dubinin–Asthakov distribution. Various adsorption mechanisms that occur in these nanoporous materials at different relative pressures can be visualized. The quantitative determination of starting mineral is described as: Ca-Clinoptilolite (88.76%) >> Montmorillonite (11.11%) >> quartz (0.13%). The Si/Al molar ratio after acid treatment is: ATH4 > ATH2 > ATN > ATH3 > ATH1. The Langmuir specific surface area (ASL) varies as follows: ATN > ATH2 > ATH4 > ATH3 > ATH1. At the same time, the VΣ values are as follows: ATN > ATH4 > ATH3 > ATH1 > ATH2.

Hydration Mechanisms of Tungsten Trioxide Revealed by Water Adsorption Isotherms and First-Principles Molecular Dynamics Simulations

WO3 is one of the most interesting materials for photocatalysis due to its optical absorption in UV–vis, good charge carrier transport, and stability against photocorrosion. A detailed knowledge of the hydration state of WO3 is indispensable to gain more precise mechanistic insights into its photocatalytic activity. To the best of our knowledge, the hydration process of WO3 has been scarcely studied so far and only from a theoretical point of view, mostly by means of static density functional theory calculations. Here, we use manometric gas sorption experiments combined with extensive ab initio molecular dynamics simulations to investigate the hydration mechanisms of WO3 at room temperature. We demonstrate that water adsorbs molecularly in a two-step mechanism: the first water sublayer interacts with the under-coordinated surface tungsten atoms through electrostatic interactions, and, in a second step, a full layer is formed through hydrogen bonds established with the pre-adsorbed water molecules and with the under-coordinated surface oxygen atoms. The computed value of −90 kJ·mol–1 for the isosteric enthalpy of adsorption of the first water molecules is in excellent agreement with the experimental value estimated using the Clausius–Clapeyron approach from the experimental adsorption isotherms. The isosteric enthalpy of adsorption steadily decreases in absolute value when the surface coverage is increased to tend toward the enthalpy of condensation of water after three adsorption layers.

Atomistic insights into the H2 adsorption and desorption behavior of novel Li-functionalized polycrystalline CNTs

At present, hydrogen storage by physisorption is being investigated on novel polycrystalline carbon nanotubes (PCNTs) in order to utilize them for large-scale applications. Large-sized nanotubes are susceptible to structural flaws known as polycrystallinity, which evolve owing to the inherent constraints of growth kinetics and purification during the synthesis process. In this study, molecular dynamics simulations (MDS) were used to analyze the adsorption and desorption behavior of PCNTs employing hybrid grand canonical Monte Carlo (GCMC) simulations coupled with microcanonical ensembles. Moreover, a distinctive potential energy distribution technique was used to compute the adsorption metrics. We further investigated the size dependency effects, including curvature, length, and grain boundaries (GBs), on hydrogen adsorption functionalities. The MDS revealed that PCNTs with a moderate grain size of 4 nm are energetically stable and adsorption compatible with maximum gravimetric densities of 8.22 and 1.03 wt% at 77 and 300 K, respectively. Furthermore, the optimized PCNTs were functionalized with Li adatoms of varied concentrations and simulated at various temperatures and pressures. Afterward, adsorption/desorption kinetics and isosteric enthalpies of Li-functionalized PCNTs (Li-PCNTs) were computed to assess the synergistic impacts of Li adatoms and GBs. Li-PCNTs have shown remarkable performance in terms of hydrogen storage and deliverability. Consequently, at 77 and 300 K, Li-PCNTs doped with a 25% adatom concentration exhibited the maximum hydrogen uptake of 10.36 wt% and 2.13 wt%, respectively. Additionally, at 300 and 77 K, the averaged isosteric enthalpy of adsorption, estimated from the adsorption isotherms, was about 7.07 kJ/mol and 4.03 kJ/mol, respectively. Therefore, despite their ability to prevent metal clustering, PCNTs have a modest impact on adsorption metrics. Our findings open up new avenues for the utilization of PCNTs in large-scale hydrogen storage applications with suitable functionalization strategies.

Study on the Calculation method of the Coal and Gas Outburst Threshold

The four undetermined parameters of the temperature-pressure-adsorption equation (TPAE) were obtained by regression of the series isothermal adsorption data of the measured middle-rank deformed coal and normal coal. The unit isosteric adsorption enthalpy (UIAE) was obtained. According to the negative value of the UIAE, adsorption is an exothermic process, desorption is an endothermic process. The coal and gas outburst threshold (OT) is defined as the product of the firmness coefficient and the unit isosteric desorption enthalpy (UIDE) to show the combined effect of adsorption thermodynamics and tectonic stress. The UIDE difference between the two coals was from 1.91 times expanded to OT difference of 5.74 times.

Influence of Chemical Pretreatment on the Adsorption of N2 and O2 in Ca-Clinoptilolite

N2 and O2 adsorption isotherms in chemically modified clinoptilolite-Ca zeolites were experimentally estimated by inverse adsorption chromatography. Natural zeolites (CLINA) were chemically treated with HCl at different concentrations (H1-H4). The adsorption of N2 and O2 on these zeolites was studied in the temperature zone of 398–498 K using gas chromatography. This technique used a thermal-conductivity detector and He as carrier gas, at a rate of 30 mL min−1. The Langmuir and Henry equations were used to describe the experimental results of these gases’ adsorption. To evaluate the selectivity of the components of atmospheric air, the chemical activation of the zeolite clinoptilolite-Ca has been carried out. The results are attractive because of the ability to separate the gases these nanomaterials present under dynamic conditions. The structural modifications of the crystalline phases of the studied zeolites were carried out through X-ray diffraction, where the average crystal size was evaluated with the Scherrer equation, finding values of 25.86 nm for CLINA and 15.12 nm for H3 zeolites. The variation of their chemical composition was carried out by energy-dispersive EDS, while the adsorption of N2 carried out their texture properties at 77 K. The selectivity coefficients (α) were evaluated for these gases in pure form and in a mixture (atmospheric air), finding the highest values in zeolites H4 and H3. The interaction energies between these gases with the porous structures of the studied zeolites were evaluated from the evolution of the isosteric enthalpies of adsorption through the Clausius–Clapeyron equation.

Study on the relationship between adsorption amounts and unit isosteric adsorption enthalpy

Study on the relationship between adsorption amounts and unit isosteric adsorption enthalpy

STUDY ON THE CALCULATION AND APPLICATION OF THE UNIT ISOSTERIC ADSORPTION ENTHALPY

A series of isothermal adsorption experimental data of lean coal and fat coal has been converted into a temperature-pressure-adsorption equation. The slop of the lnP vs 1/T straight line of Clausius-Clapeyron equation proves that physical adsorption is an exothermic process. The Unit Isosteric Adsorption Enthalpy (UIAE, KJ•mol-1•cm-3•g) is defined as a unit adsorbed amount enthalpy at a fixed adsorbed amount andthe calculation method is presented. The UIAE calculation results prove the surface of the adsorption medium is not uniform, and the interaction between the adsorption molecules occurs. At the same isosteric adsorption condition, lean coal has higher priority to carry out the exothermic process than the fat coal.

A Better Understanding of the SBA-15 Pores Filling through Textural Changes in CMK-3 Carbon Synthesis and Its CO2:CH4 Adsorption Selectivity

This text reports the morphological and textural behavior of the synthesis stages of a CMK-3 carbon type using a silicon matrix of the SBA-15 type calcined at 823 K as a template. During the synthesis, three intermediate materials were obtained because of (i) the addition of sucrose to the SBA-15 template (CCMK3-1st), (ii) the addition of sucrose to the CCMK3-1st material (CCMK3-2nd), and (iii) the carbonization by pyrolysis of the by-product CCMK3-2nd (CCMK3-F). The texture of the above materials was found by analyzing the N2 adsorption isotherms, applying the classical adsorption theories to obtain the BET-specific surface and the meso- and micropore distributions by the BJH and Dubinin–Astakhov (DA) methods, respectively, in addition to the non-localized density functional theory (NLDFT). Similarly, with high resolution, the samples were analyzed morphologically by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Finally, the adsorption isotherms of CO2 and CH4 of the CMK-3 sample were obtained at six different temperatures in the interval of 243 to 303 K to evaluate the behavior of the isosteric enthalpy of adsorption (qst) and its CO2:CH4 ideal selectivity. The final CMK-3 carbon presented two families of micro- and mesopores of 1.5 and 3.2 nm, nanopipe diameters of 3.5 nm, and a specific surface area of 1350 m2/g. It also presented values of 6.0 and 2.4 mmol/g adsorbed CO2 and CH4 at 243 K, respectively, and strong intermolecular interactions, with qst values higher than 22 kJ/mol reflected in high selectivity values for an ideal mixture of CO2:CH4 (30:70%).

Adsorption characteristics and thermodynamic analysis of shale in northern Guizhou, China: Measurement, modeling and prediction

The Lower Cambrian Niutitang Formation shale is the principal organic-rich shale formation in the northern Guizhou Province of China, which has great shale gas development prospects. In this study, the isothermal adsorption data from 26 shale samples from Niutitang Formation in northern Guizhou were obtained through the isothermal adsorption experiment of self-sampled specimens, along with published data. On this basis, we analyzed the control effects of temperature and physical parameters on adsorption capacity. An adsorption model with two new physical meaning parameters was constructed, and the accuracy of the model was validated. In addition, the isosteric enthalpy of adsorption in shale was further calculated, and the factors that affected the isosteric enthalpy were discussed. The results showed that the isosteric enthalpy decreased with an increase in temperature, and increased with an increase of TOC, but was controlled at a higher TOC. TOC-normalized heat revealed a more obvious segmental change rule for thermal maturity. Finally, we provided a new method to predict adsorption isotherms at other temperature conditions through the isosteric enthalpy of adsorption, and obtained better prediction results. This study provided a new insight for further understanding of shale adsorption characteristics from the perspective of thermodynamics.

Binary dyes adsorption onto novel designed magnetic clay-biopolymer hydrogel involves characterization and adsorption performance: Kinetic, equilibrium, thermodynamic, and adsorption mechanism

Nowadays, the treatment of dyes and pigments was considered a serious challenge in the world. In this work, a novel high-performance magnetic bio-based κ-carrageenan-kaolinite hydrogel (CKAlFe) was designed, characterized, and used for the simultaneous adsorption of Alizarin red and Congo red dyes from an aqueous solution. The morphological characterization revealed the successful preparation of non-rigid and plate-like CKAlFe adsorbent with the microporosity structure, in which the κ-carrageenan forms the amorphous part and kaolinite clay, Al2O3, and Fe3O4 are involved in the crystalline part of the structure. It was found as an efficient adsorbent with maximum adsorption capacities of 26.9 and 33.5 mg/g toward Congo red and Alizarin red molecules respectively. The adsorption capacity of CKAlFe was decreased in acidic media. The adsorption kinetics followed the pseudo-second-order kinetic model. The intra-particle diffusion controlled the adsorption rate at low initial concentrations, while the transfer rate of molecules from solution to the surface of CKAlFe played this role at higher concentrations. Also, the adsorption isotherm followed the extended Langmuir isotherm model. The thermodynamic study demonstrated that Congo red and Alizarin red binary adsorption onto CKAlFe was endothermic and spontaneously occurred, while Alizarin red molecules required more energy than Congo red to be adsorbed and a higher fraction of the active sites were occupied by Congo red molecules. The mechanism study showed that multiple interactions including π-π stacking, electrostatic interaction, dipol-dipol H bonding, and Yoshida H bonding can be involved in the adsorption process of studied dyes onto CKAlFe. Besides, the isosteric enthalpy of adsorption revealed that the adsorption type varied from physical to chemical process, increasing the amount of adsorbed dyes. The prepared magnetic hydrogel is highly capable of being used in drug delivery for selectively detection, hyperthermia/thermal ablation, and different products already on the market.

Decolorization of xylose mother liquor with polydivinylbenzene/aminated polyglycidyl methacrylate interpenetrating polymer networks

ABSTRACT An interpenetrating polymer network originating from the physical entanglement of polydivinylbenzene and aminated polyglycidyl methacrylate (PDVB/PMATAM resin) was prepared for the decolorization of xylose mother liquor, and its adsorption performance and mechanism were explored. The resin had a good decolorization effect on the xylose mother liquor, and the decolorization of xylose mother liquor over the resin was completed within a short time due to the synergic effect of hydrophobicity and hydrophilicity. The resin tended to absorb phenols in comparison to sugar, resulting in a high removal rate of phenols and a low loss rate of sugar for xylose mother liquor. The adsorption of pigment impurities on the resin could be described well by a pseudo-second-order model, and its isothermal adsorption process followed Langmuir model. The isosteric adsorption enthalpy of the resin decreased with increasing the fractional loading of pigment impurities, and the distribution of adsorption site on the resin was inhomogeneous. The saturation adsorption capacity of pigment impurities in the fixed-bed column packed by the resin reached up to 14 times of the resin volume, and the reusability of the resin basically remained constant, which shows a good application prospect.

Evaluation of the Adsorptive Process on Adsorbent Surfaces as a Function of Pressure in an Isosteric System Compared with Adsorption Isotherm

The developing significance of adsorption has brought about a steadily expanding quantity of logical and innovative writing on different adsorbents. This paper intends to propose experimental and computational methods for measuring the strength of adsorbate–solid interactions. It primarily focuses on the use of graphs to measure the effectiveness of an adsorbate’s bonds with the solid adsorbent by determining the isosteric heat. The Clausius–Clapeyron model equation is used to determine the isosteric enthalpy of adsorption from two adsorption isotherms at various but close temperatures, with ΔT of 10 °C. A full computational explanation of the Clausius–Clapeyron model equation for determining ΔHads is provided using experimental data. Logarithmic plots of uptakes vs. p in the low-pressure zone for the Freundlich–Langmuir graph are used to assess and confirm the quality of the crucial underlying isotherms. The isosteric heat was found to be between 13.5 kJ/mol and 16 kJ/mol.

Nanoporosity and Isosteric Enthalpy of Adsorption of CH4, H2, and CO2 on Natural Chabazite and Exchanged

This paper describes the isosteric enthalpy through narrow pores at low levels of coverage through adsorption of CO2, CH4, and H2 on pores in natural chabazite exchanged with aqueous solutions of Na+, Mg2+, and Ca2+ salts at different concentrations, and with variable time and temperature of treatment. Experimental data of CO2, CH4, and H2 adsorption were treated by the Freundlich and Langmuir equations. Complementarily, the degree of interaction of these gases with these zeolites was evaluated by the evolution of isosteric enthalpy of adsorption. The exchange with Mg2+ and Na+ favors an increase in the adsorption capacity for CO2. while that of Ca2+ and Mg2+ favor adsorption through to H2 and CH4. These cations occupy sites in strategic positions S4 and S4’, which are located in the channels and nanocavities of these zeolites. The presence of Ca2+ and Mg2+ at S4 and S4′ sites causes increased adsorption into the nanocavities and on the external area of the ion-exchanged zeolites. Depending on the conditions of the exchange treatment, Ca2+ and Mg2+, and Na+ were found to be most favorable, well distributed, and accessible for CO2, CH4, and H2 adsorption.

A Microporous Potassium‐Organic Framework for Efficient C2H2/CO2 Separation

AbstractA novel potassium‐based metal organic framework (TCBPA‐K) was prepared by using a C3‐symmetric organic building block tris(4′‐carboxybiphenyl)amine (TCBPA). The compound has a rectangular like channel along the b axis and exhibits good selective adsorption performance. The single component gas adsorption isotherms indicated that the adsorption capacity of C2H2 is much higher than that of CO2 at 298 K and 1 bar. The isosteric adsorption enthalpies of TCBPA‐K for C2H2 and CO2 are 30.6 kJ/mol and 9.1 kJ/mol respectively. Ideal adsorbed solution theory calculation recorded the separation selectivity of C2H2/CO2 (50/50, v/v) as 3.5.