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Journal articles on the topic 'Heats of adsorption'

Author: Grafiati

Published: 4 June 2021

Last updated: 18 June 2025

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1

S., A. Anjorin. "Determination of Adsorption Heats of Some Adsorbents on Ammonia." European Journal of Advances in Engineering and Technology 5, no. 12 (2018): 933–38. https://doi.org/10.5281/zenodo.10727512.

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<strong>ABSTRACT</strong> Adsorption is accompanied by the evolution of heat.  In this paper, adsorption isotherms were measured, at the pressure range of 6.67-53.33 kPa and at the temperature range of 303-353 K, for some adsorption working pairs: Charcoal –NH<sub>3</sub>, CaCl<sub>2 </sub>– NH<sub>3 </sub>and CaCl<sub>2 </sub>composites – NH<sub>3</sub>. Isosteric heats of adsorption were determined from these isotherms.  Values of isosteric heat of adsorption ranged between 13.94 and 50.71 kJ/mol for Charcoal, Charcoal + calcium chloride and calcium chloride + silica gel. 75% CaCl<sub>2 </sub>+ 25% CaSO<sub>4 </sub>had the least value of isosteric heat of adsorption whilst 75% CaCl<sub>2 </sub>+  25% charcoal had the highest value.

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2

Goncharuk, V. V., V. F. Gorchev, and S. A. Karakhim. "A New Approach for Modelling Heterogeneous Surfaces." Adsorption Science & Technology 14, no. 6 (1996): 375–82. http://dx.doi.org/10.1177/026361749601400605.

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In present work, the scope of a new approach for modelling heterogeneous surface isotherms and differential adsorption heats for a discrete heterogeneous surface with three kinds of sites has been examined. All the various kinds of experimentally observed dependencies of the differential adsorption heats on the surface coverage described in the literature have been reproduced. The increase in differential adsorption heat with surface coverage of a heterogeneous surface has been shown to be possible when the pre-exponential factor changes in moving from one kind of site to another. In this connection, it has been proposed that the heterogeneous surface should be characterized not only by the dependence of the adsorption heats on the distribution of active sites but also by the adsorption coefficient. The parameters for the adsorption of propan-2-ol on γ-aluminium oxide have been calculated from adsorption/calorimetric data.

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3

Giraldo, Liliana, Paola Rodriguez-Estupiñán, and Juan Carlos Moreno-Piraján. "Isosteric Heat: Comparative Study between Clausius–Clapeyron, CSK and Adsorption Calorimetry Methods." Processes 7, no. 4 (2019): 203. http://dx.doi.org/10.3390/pr7040203.

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This work presents the calorimetric study of five adsorbents with different chemical and textural characteristics: MOF-199, MCM-41, SBA-15, activated carbon prepared from corn cob (GACKP) and graphite. These solids were used to establish the differences between isosteric heats evaluated by three different methods: Clausius–Clapeyron (C-C), Chakraborty, Saha and Koyama (CSK) and Adsorption Calorimetry (A-Cal). The textural characterization results show solids that have values of specific surface area between 2271 m2·g−1 for the MOF-199 and 5.2 m2·g−1 for the graphite. According to the results obtained for the isosteric heats for each sample, the magnitude varies depending on the coverage of the adsorbate and the textural characteristics of each adsorbent. Solids with an organized structure have isosteric heat values that are coincident among the three methods. Meanwhile, heterogeneous solids such as activated carbon values evaluated by the CKS and C-C have a high dispersion method regarding the adsorption calorimetry method. The results obtained show that the adsorption calorimetry, being a direct experimental measurement method, presents less dispersed data. At low quantities, the isosteric heat of nitrogen adsorption decreased in the order MOF-199, GACKP, MCM-41, SBA-15 and Graphite. The order for the isosteric heats values was coherent with the surface characteristics of each of the solids, especially with the pore size distribution. Finally, throughout the coverage examined in this work, the isosteric heats for nitrogen adsorption determined by adsorption calorimetry (A-Cal) were larger than the evaluated by C-C and CSK indirect methods of vaporization. According to the results, it is shown that the adsorption calorimetry allows values of the isosteric heats of adsorption with an error of less than 2% to be established and also reveals the complex nature of the heterogeneity or homogeneity of the adsorbent.

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4

Liu, Xiuying, Jie He, and Rui Li. "High-Pressure Hydrogen Adsorption in the Zeolites: A Grand Canonical Monte Carlo Study." ISRN Renewable Energy 2012 (July 8, 2012): 1–4. http://dx.doi.org/10.5402/2012/491396.

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The adsorption of hydrogen molecules on different zeolites at near room temperature and extremely high pressures has been simulated employing Grand Canonical Monte Carlo (GCMC) method. Some important physical amounts under different temperatures and pressures, such as adsorption isotherms, adsorption amounts, and isosteric heats were studied. We predict the storage capacity of hydrogen in ZON and CHA zeolites at different conditions. The results show that the hydrogen storage capacity of CHA is superior to that of ZON. The different hydrogen adsorption behavior between them is explained by the isosteric heats of adsorption at different temperatures. These results may help us to understand different hydrogen adsorption properties of these two zeolites, thus facilitate exploring new hydrogen storage candidates experimentally.

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5

Zhou, Su-Qin, Yang-Yang Wu, Si-Yu Xu, Feng-Qi Zhao, and Xue-Hai Ju. "Oxygen adsorption and diffusion on an Al(111) surface and subsurface: a theoretical study." Canadian Journal of Chemistry 94, no. 6 (2016): 541–46. http://dx.doi.org/10.1139/cjc-2015-0278.

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The generalized gradient approximation of the density functional theory was used to investigate the adsorption and dissociation of the O2 molecule on an Al(111) surface and the subsequent diffusion of an oxygen atom into the subsurface with different oxygen coverages. The total adsorption energies of oxygen atoms on the Al(111) surface increase as the number of adsorbed oxygen atoms increases, while the adsorption heats per oxygen atom decrease firstly and then increase. The adsorption heats for O2 physisorption on the Al(111) surface would increase as the oxidization degree of Al(111) surface increased. As the oxidization degree of Al(111) surface increases, the adsorption heats for O2 chemisorption decrease firstly and then increase, and the O2 molecule would not dissociate when the oxidization degree was up to 1.0 monolayer. In general, the energy barriers for both the interlayer and intralayer diffusions of the oxygen atom on the Al(111) surface would become larger as the number of initial adsorbed oxygen atoms on the Al(111) surface increased due to an increasing repulsion force.

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6

Möller, P., and H. Papp. "Heats of Adsorption and Reaction of CO on Iron/Manganese Oxide Catalysts." Adsorption Science & Technology 4, no. 3 (1987): 176–84. http://dx.doi.org/10.1177/026361748700400303.

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The heats of adsorption and reaction of CO have been measured on reduced Fe/Mn oxide catalysts of different compositions at temperatures between 263 and 543 K. The heats of adsorption depend only to a small extent on the manganese content of the catalyst and are independent of the temperature of reduction. The former fact points to a more structural than electronic effect of the manganese oxide addition. The heats of adsorption are, however, strongly dependent on measurement temperature, increasing from about 60 kJ mol-1 at 263 K to about 200 kJ mol-1 at 493 K and then decreasing again to about 180 kJ mol-1 at 543 K. This temperature dependence can be explained by consecutive reactions following CO adsorption, i.e. the Boudouard reaction, dissociation of CO and diffusion of carbon into the bulk of iron. The amount of CO adsorbed is correlated to the metallic iron content in the surfaces of the catalysts.

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7

Rossi, Pier Francesco, та Paola Rossi. "Heats of Adsorption of Aliphatic Alcohols on α-Al2O3 at 25–200°C. I. Variations with Experimental Temperature". Adsorption Science & Technology 13, № 4 (1996): 215–29. http://dx.doi.org/10.1177/026361749601300401.

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The process of adsorption of five aliphatic alcohols (C1–C5) on α-Al2O3 in the temperature range 25–200°C has been studied by means of a Calvet microcalorimeter (moderately high temperature) equipped with a volumetric ramp. The calorimetric and volumetric isotherms indicate that the integral heats released and the amounts of alcohols adsorbed decreased as the experimental temperature increased. All the volumetric isotherms follow the Langmuir isotherm trend, i.e. type I isotherms. The differential heats of the five alcohols on α-alumina were very high (>250 kJ/mol) at very low coverages at all temperatures and decreased rapidly towards the heat of vaporization of the alcohols at higher coverages. The trends in the differential heats of adsorption as a function of the number of μmol of MeOH, EtOH, and 1-PrOH adsorbed appear to be different from those for 1-BuOH and 1-PeOH (1-pentanol) at the different temperatures studied. Increasing the adsorption temperature made the trends in the differential heats more pronounced, with the alumina surface requiring smaller amounts of adsorbed alcohol to effect its saturation.

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8

Kuznetsov, B. V., Ninh Anh Tuan, and T. A. Rachmanova. "Calorimetric and Isosteric Heats of Adsorption of Substances with Molecules of Different Electronic Structure." Adsorption Science & Technology 6, no. 1 (1989): 27–34. http://dx.doi.org/10.1177/026361748900600104.

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Calorimetric heats of adsorption have been measured for iso- and cyclo-pentane on NaX(86) zeolite at 140°C and for acetonitrile on carbon black and silica gel at 150°C. These heats have been compared with the corresponding isosteric values, calculated from isotherms measured over temperature ranges whose average values correspond to the above temperatures. The isosteric heats of adsorption coincide well with the calorimetric values in those cases where no change occurs in the mechanism for adsorbate–adsorbent interaction within the temperature range over which the isotherms have been measured. If this condition is not observed, the difference between the two sets of values can be quite considerable.

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9

Al-Zaid, Khairya, Saed Akashah, Fathi Owaysi, G. V. Jeffreys, Yu A. Eltekov, and C. Mumford. "Adsorption of Aromatic Compounds from Solutions on Molecular Sieve 13X." Adsorption Science & Technology 4, no. 3 (1987): 196–210. http://dx.doi.org/10.1177/026361748700400305.

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Measurements of the equilibrium extent of adsorption of individual aromatic hydrocarbons: mono, di, trinuclear aromatic and heterocyclo compounds from iso-octane solutions by molecular sieves 13X were carried out at 303 and 343 K and at concentrations up to 5 wt.% The limiting values of adsorption were essentially determined by using modified Brunauer-Emmett-Teller equation (BET). The coverages and numbers of adsorbate molecules occupied in the unit cell of the molecular sieves were calculated at different temperatures. The isosteric heats of adsorption of aromatic hydrocarbons were also determined using Clausius-Clapeyron equation. It was found that the heats of adsorption of aromatic compounds varied from 4 to 60 kJ mol-1

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10

Rakhmatkarieva, Firuza, Odina Davlatova, Mirzokhid Kokhkharov, et al. "Mechanism of H₂O Vapor Adsorption in A Type Zeolites: A Model Based on Adsorption Calorimetry." E3S Web of Conferences 434 (2023): 03032. http://dx.doi.org/10.1051/e3sconf/202343403032.

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In this study, the energy characteristics of water vapor adsorption in NaA and NaA(NaBO2) zeolites were measured by adsorption calorimetry. Information of differential heats, isotherms, entropy and kinetic of adsorption in the matrix of NaA and NaA(NaBO2) zeolites were obtained. Adsorption isotherms (a) and differential heats of adsorption (Qd) of water vapor by NaA and NaA(NaBO2) zeolites were measured at 303 K. The heats of adsorption are stepwise and each step corresponds to the stoichiometric formation of adsorption complexes of H2O molecules with Na+ or H+ ions, (H2O)n/Na+ or H+, (n = 1-4), which are located on the SIII, SII and SI crystallographic positions of NaA and NaA(NaBO2). Hydration mechanism of NaA and NaA(NaBO2) are complex and at saturation, the zeolites are occupied by the next water zeolitic host/guest systems: NaA – 2.2[(H2O)4/Na+III+H+], 3[(H2O)2/Na+II] and 6.6[(H2O)2/Na+I]; NaA(NaBO2) - 2[(H2O)4/Na+III], 3[(H2O)4/Na+II] and 6.86[(H2O)/Na+I]. The complete hydration of the α- and β cages of NaA amounts thus to 21,8 and 6,2 respectively H2O/u.c. and α-cage of NaA(NaBO2) – 26,3 H2O/u.c. The mean molar integral adsorption entropy of water is ~-30,5 J/mol K less than the entropy of the bulk liquid. This value nearly the same as entropy of crystalline water so the mobility of water in the zeolitic matrix is solidlike.

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11

Gatta, Giuseppe Della. "Direct determination of adsorption heats." Thermochimica Acta 96, no. 2 (1985): 349–63. http://dx.doi.org/10.1016/0040-6031(85)80074-5.

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12

Nieszporek, Krzysztof. "Application of the Integral Equation Approach to the Study of Enthalpic Effects Accompanying Mixed-Gas Adsorption on Heterogeneous Solid Surfaces." Adsorption Science & Technology 20, no. 3 (2002): 243–60. http://dx.doi.org/10.1260/026361702760254432.

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The possibilities of the Integral Equation approach for describing mixed-gas adsorption equilibria are presented. In this study, the energetic heterogeneity was described through the use of the Gaussian-like adsorption energy distribution function. As a result, very simple equations describing the isosteric heats of mixture components were obtained. The advantage of the model presented is the possibility of predicting the phase diagrams and enthalpic effects accompanying mixed-gas adsorption from a theoretical viewpoint based on pure-component adsorption data. New equations for isosteric heats of component mixtures were examined using the experimental data obtained by Dunne et al. (1996a, b, 1997), i.e. C2H6, CH4 adsorbed on silicalite and CO2, C2H6 adsorbed on NaX zeolite. The calculations are relatively simple and can be applied industrially.

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13

Gurnagul, N., and D. G. Gray. "Surface adsorption at low coverage of n-alkanes on bleached kraft papers using gas chromatography." Canadian Journal of Chemistry 65, no. 8 (1987): 1935–39. http://dx.doi.org/10.1139/v87-323.

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The adsorption at low surface coverage of a series of n-alkanes on various bleached kraft paper surfaces was measured by gas chromatography. Differences in surface area of the paper samples were readily measured from the gas chromatographic retention volumes. The standard free energy, the enthalpy, and the entropy of adsorption varied linearly with the number of carbon atoms in the n-alkanes. The heats of adsorption were close to the heats of liquefaction, indicating the non-specific interactions of the hydrocarbons with the bleached kraft surfaces. The London component of the surface free energy was estimated from the gas chromatographic results to be 47.9 mN/m.

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14

Abdulkhaev, Tolibjon, Shakhnoza Kuldasheva, Gulnara Raximova, Mukarram Aripova, and Sherzod Toshev. "Thermodynamic values of the adsorption of methanol and ethanol molecules in zeolite NH4ZSM-5." IOP Conference Series: Earth and Environmental Science 839, no. 4 (2021): 042074. http://dx.doi.org/10.1088/1755-1315/839/4/042074.

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Abstract Differential heats, isotherm, entropies and thyromimetics of methanol and ethanol adsorption in the NH4ZSM-5 zeolite were measured at 303K. The isotherm of adsorption was quantitatively reproduced on the basis of TVOM theory. The detailed mechanism of methanol and ethanol adsorption in (NH4)1,35ZSM-5 zeolite from zero filling to saturation was discovered.

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15

Thirion, D., V. Rozyyev, J. Park, et al. "Observation of the wrapping mechanism in amine carbon dioxide molecular interactions on heterogeneous sorbents." Physical Chemistry Chemical Physics 18, no. 21 (2016): 14177–81. http://dx.doi.org/10.1039/c6cp01382a.

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16

Whittaker, Peter B., Xiaolin Wang, Klaus Regenauer-Lieb, and Hui Tong Chua. "Predicting isosteric heats for gas adsorption." Phys. Chem. Chem. Phys. 15, no. 2 (2013): 473–82. http://dx.doi.org/10.1039/c2cp41756a.

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17

Isirikya, A. A., M. A. Levin, V. V. Serpinskii, and A. A. Fomkin. "Gas adsorption heats at elevated pressures." Bulletin of the Academy of Sciences of the USSR Division of Chemical Science 36, no. 7 (1987): 1535–37. http://dx.doi.org/10.1007/bf01557544.

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18

Thamm, H., H. Stach, E. Jahn, and B. Fahlke. "Calorimetric Investigation of the Adsorption Properties of Microporous Aluminophosphate AlPO4−5." Adsorption Science & Technology 3, no. 4 (1986): 217–20. http://dx.doi.org/10.1177/026361748600300401.

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Differential heats of adsorption have been measured calorimetrically for benzene and n-hexane on AlPO4-5. Adsorption isotherms have been determined for benzene, n-hexane and H2O. The heat of adsorption for benzene on AlPO4-5 was found to be less than the heat of adsorption for n-hexane. Isotherms of all adsorbates investigated exhibited hysteresis loops. The hydrophilicity of AlPO4-5 is explained by capillary condensation and/or coordinately bonded water.

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19

Iheanacho, Ositadinma Chamberlain, Joseph Tagbo Nwabanne, Christopher Chiedozie Obi, Chinenye Adaobi Igwegbe, Chijioke Elijah Onu, and Irvan Dahlan. "Adsorptive Dephenolization of Aqueous Solutions Using Thermally Modified Corn Cob: Mechanisms, Point of Zero Charge, and Isosteric Heat Studies." Adsorption Science & Technology 2023 (April 13, 2023): 1–14. http://dx.doi.org/10.1155/2023/2813663.

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The sorption mechanisms, point of zero charge, and isosteric heats involved in the adsorptive dephenolization of aqueous solutions using thermally modified corn cob (TMCC) were studied at different initial phenol concentrations (100–500 mg/l), TMCC dosage (0.4–2.0 g), contact time (5–60 min), pH (2–10), and temperature (30–60°C). Analysis of the adsorbent material showed that it possessed the properties typical of a good adsorbent. The adsorption experiments revealed that phenol uptake is favored by an increase in TMCC dosage and contact time and a decrease in temperature and concentration of phenol in the solution. The experimental data were well-fitted to the Sips, Langmuir, Toth, and Redlich–Peterson isotherm models. Thermodynamic studies suggested that the sorption of phenol onto TMCC is feasible, spontaneous, and endothermic. The isosteric heats of adsorption obtained are in the range 47.43-79.38 kJ/mol, confirming that the adsorption process is predominantly a physical process depicting the van der Waals interactions, and it is inversely proportional to surface loading. The analysis of the adsorption mechanisms showed that the intraparticle, film, and pore diffusion mechanisms were significantly involved in the phenol adsorption process. The involvement of electrostatic attraction, π ‐ π electron-donor interaction, and hydrogen bonding was also demonstrated. The point of zero charge ( p H pzc ) was obtained at a pH of 5.83; being slightly lower than the optimum pH of 6 indicates that the sorbent surface is obviously not negatively charged at p H pzc . The discoveries of this study have shown that the dephenolization process is feasible, spontaneous, endothermic, dominated by a physical process, and governed by intraparticle, film, and pore diffusion mechanisms.

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20

Mauer, Volker, Christian Bläker, Christoph Pasel, and Dieter Bathen. "Energetic Characterization of Faujasite Zeolites Using a Sensor Gas Calorimeter." Catalysts 11, no. 1 (2021): 98. http://dx.doi.org/10.3390/catal11010098.

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In addition to the adsorption mechanism, the heat released during exothermic adsorption influences the chemical reactions that follow during heterogeneous catalysis. Both steps depend on the structure and surface chemistry of the catalyst. An example of a typical catalyst is the faujasite zeolite. For faujasite zeolites, the influence of the Si/Al ratio and the number of Na+ and Ca2+ cations on the heat of adsorption was therefore investigated in a systematic study. A comparison between a NaX (Sodium type X faujasite) and a NaY (Sodium type Y faujasite) zeolite reveals that a higher Si/Al ratio and therefore a smaller number of the cations in faujasite zeolites leads to lower loadings and heats. The exchange of Na+ cations for Ca2+ cations also has an influence on the adsorption process. Loadings and heats first decrease slightly at a low degree of exchange and increase significantly with higher calcium contents. If stronger interactions are required for heterogeneous catalysis, then the CaNaX zeolites must have a degree of exchange above 53%. The energetic contributions show that the highest-quality adsorption sites III and III’ make a contribution to the load-dependent heat of adsorption, which is about 1.4 times (site III) and about 1.8 times (site III’) larger than that of adsorption site II.

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21

Bulnes, F., A. J. Ramirez-Pastor, and G. Zgrablich. "Monte Carlo Simulation of the Adsorption of Binary Gas Mixtures on Heterogeneous Surfaces." Adsorption Science & Technology 23, no. 2 (2005): 81–93. http://dx.doi.org/10.1260/0263617054037826.

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The adsorption of a gaseous mixture containing particles A and B was studied via lattice-gas simulations on homogeneous and heterogeneous bivariate surfaces characterized by a chessboard topography of strong and weak adsorbing sites. The effects of lateral interactions among adsorbed particles and of heterogeneity on the adsorption isotherms and differential heats of adsorption were analyzed. The results displayed a rich variety of behaviours and their analysis contributes to the understanding of mixed-gas adsorption at a molecular level.

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22

Al-Zaid, Khairya, Saed Akashah, Fathi Owaysi, G. V. Jeffreys, C. Mumford, and Yu A. Eltekov. "Adsorption of Aromatic Mixtures from Solutions by Molecular Sieve 13X." Adsorption Science & Technology 4, no. 3 (1987): 185–95. http://dx.doi.org/10.1177/026361748700400304.

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Adsorption isotherms of 3 extracts (concentrated aromatics) have been determined on molecular sieve 13X from solution in iso-octane at 303 and 343 K. The concentration of aromatic compounds before and after adsorption was determined using ultraviolet spectroscopic method of analysis. Values of the adsorption capacity and adsorption coefficient were determined from an equation for pore filling model. The three extract fractions showed a strong affinity for adsorption by molecular sieve. Heats of adsorption of the 3 extract fractions were calculated from adsorption and found to be in the range of 4-20 kJ mol-1.

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23

Kichukova, Diana, Tsvetomila Lazarova, Genoveva Atanasova, Daniela Kovacheva, and Ivanka Spassova. "Tailored Carbon Nanocomposites for Efficient CO2 Capture." Molecules 30, no. 11 (2025): 2408. https://doi.org/10.3390/molecules30112408.

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CO2 capture by adsorption on proper solid materials appears to be a promising approach, due to its low energy requirements and ease of implementation. This study aimed to prepare efficient materials for CO2 capture based on composites of nanocarbon and reduced graphene oxide, using graphite, L-ascorbic acid, and glycine as precursors. The materials were characterized by XRD, low-temperature N2 adsorption, FTIR, Raman, and XPS spectroscopies, along with SEM and TEM. The CO2 adsorption capacities, heats of adsorption, and selectivity were determined. A hierarchical porous structure was found for NC-LAA, NC/RGO-LAA, and NC/RGO-Gly. At 273 K and 100 kPa, the adsorption capacities for NC-LAA and NC-Gly reached 2.6 mmol/g and 2.5 mmol/g, respectively, while for the composites, the capacities were 1.7 mmol/g for NC/RGO-Gly and 3.5 mmol/g for NC/RGO-LAA. The adsorption ability of the glycine-derived materials is related to the presence of nitrogen-containing functional groups. The heats of adsorption for NC-LAA, NC-Gly, and NC/RGO-Gly reveal chemisorption with CO2. Except for chemisorption, the NC/RGO-LAA material shows a sustained physical adsorption up to higher CO2 coverage. The best adsorption of CO2, observed for NC/RGO-LAA, is connected with the synergy between carbon dots and RGO. This composition ensures both sufficient oxygen surface functionalization and a proper hierarchical porous structure.

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24

Almáši, Miroslav, Vladimír Zeleňák, Arnošt Zukal, Juraj Kuchár, and Jiří Čejka. "A novel zinc(ii) metal–organic framework with a diamond-like structure: synthesis, study of thermal robustness and gas adsorption properties." Dalton Transactions 45, no. 3 (2016): 1233–42. http://dx.doi.org/10.1039/c5dt02437d.

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A novel 3D metal–organic framework with a diamond-like structure has been synthesised and structurally characterized. Adsorption of Ar, CO<sub>2</sub>, H<sub>2</sub> and N<sub>2</sub> has been studied. Heats of CO<sub>2</sub> and H<sub>2</sub> adsorption were calculated according to the Clausius–Clapeyron equation.

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25

Cahyanti, Margareta Novian, and Alvama Pattiserlihun. "Thermodynamic Properties of Water Adsorption on Gaplek Flour Fortified with Red Bead Tree Seed." Molekul 13, no. 2 (2018): 114. http://dx.doi.org/10.20884/1.jm.2018.13.2.411.

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The moisture sorption isotherm data of gaplek flour fortified with red bead tree seed stored in a chamber, the relative humidity of chamber ranging from 10% to 97% regulated using a saturated salt solution, was determined at three temperatures 25°, 35°, and 45 °C. The experimental data used to determine the thermodynamic functions were isosteric heat of sorption, sorption entropy, and free energy changes. The sorption isosteric heats were determined by the application of the Clausius–Clapeyron equation. Isosteric heats of adsorption increased to maximum level and then declined with increase of moisture content. Adsorption entropy increased to maximum level and then declined with the increase of moisture content. The free energy changes increased with increase in moisture content. The spreading pressure increased with increasing water activity.

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26

Raxmatkarieva, Firuza Gayratovna Davlatova Odina Zakirjonovna. "ENERGETICS OF THE HOST-GUEST INTERACTIONS IN NALTA MOLECULAR SIEVES. THE STEPWISE NATURE OF THE HEAT CURVE OF ADSORPTION." EURASIAN JOURNAL OF MEDICAL AND NATURAL SCIENCES 2, no. 12 (2022): 217–22. https://doi.org/10.5281/zenodo.7353193.

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27

Rakhmatkarieva, F., O. Ergashev, O. Davlatova, et al. "NalTA energy in molecular sieve guest-guest interactions energetics of host-guest interactions in NalTA molecular electrics." Journal of Physics: Conference Series 2388, no. 1 (2022): 012175. http://dx.doi.org/10.1088/1742-6596/2388/1/012175.

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Abstract The paper analyzes the isotherm and differential heats of adsorption of carbon dioxide in NaLTA and establishes the molecular host-guest mechanism of interactions in the molecular sieve matrix.

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28

Stach, H., J. Jänchen, H. Thamm, E. Stiebitz, and R. A. Vetter. "Influence of the Pore Diameter on the Adsorption Behaviour of Nonpolar Molecules on SiO2-Adsorbents." Adsorption Science & Technology 3, no. 4 (1986): 261–70. http://dx.doi.org/10.1177/026361748600300407.

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The adsorption equilibrium of n-paraffins (ethane, n-butane, n-hexane and n-decane) and some noble gases on SiO2-adsorbents with different pore diameter have been investigated using the techniques of isostere-, isotherm- and calorimetric-measurements. There is a strong influence of the pore diameter on the adsorption potential. As the pore diameter of the adsorbents increases the adsorption enthalpy decreases while the adsorption entropy increases. For the initial heats of adsorption of the n-alkanes an empirical equation is derived, allowing the calculation of the thermodynamic data in advance, knowing the (mean) pore diameter.

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29

Ergashev, Oybek, and Olimjon Nuridinov. "Isotherms of differential heat and entropy adsorption of carbonyl sulfide in zeolite NaX when cleaning gases." E3S Web of Conferences 390 (2023): 05042. http://dx.doi.org/10.1051/e3sconf/202339005042.

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The task of this research cycle was to measure adsorption isotherms (а) in the temperature range from 273 to 373 K, based on isotherms measured at different temperatures, to calculate isosteric heats (Qd) and entropies (∆Sd) of adsorption in order to select an effective adsorbent for purifying natural gas and oil products from sulfur-containing compounds. This article presents the results of studies of the isotherms of COS adsorption on NaX, carried out at four temperatures: 273, 298, 303, and 373 K, and the corresponding thermodynamic functions of adsorption in NaX zeolite.

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30

Mamadjonova, Mohfora, and Nuridinov Olimjon. "Investigation of isotherms of differential heat-entropy adsorption of carbonyl sulfide in CaA zeolite during gas purification." E3S Web of Conferences 390 (2023): 05039. http://dx.doi.org/10.1051/e3sconf/202339005039.

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The task of this research cycle was to measure adsorption isotherms (а) in the temperature range from 273 to 373 K, based on isotherms measured at different temperatures, to calculate isosteric heats (Qd) and entropies (∆Sd) of adsorption in order to select an effective adsorbent for purifying natural gas and oil products from sulfur-containing compounds. This article presents the results of studies of the isotherms of COS adsorption on CaA, carried out at four temperatures: 273, 298, 303, and 373 K, and the corresponding thermodynamic functions of adsorption in CaA zeolite.

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31

Rudzinski, W., and J. Jagiello. "A Simple Approach to the 2D Mobile Adsorption of Gases on Heterogeneous Solid Surfaces Exhibiting Random Surface Topography." Adsorption Science & Technology 6, no. 1 (1989): 35–51. http://dx.doi.org/10.1177/026361748900600105.

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Based on a summation to infinity of the virial expansion for the 2D compressibility factor, simple equations have been developed for adsorption isotherms, and heats of adsorption, of 2D dense mobile films adsorbed on solid surfaces. They have subsequently been generalized for the presence of an external, randomly varying potential field, created by the random surface topography exhibited by heterogeneous solid surfaces.

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32

Prasad, Madhu, B. S. Akkimaradi, S. C. Rastogi, Radhika Rani Rao, and K. Srinivasan. "Heats of adsorption for charcoal nitrogen systems." Carbon 37, no. 10 (1999): 1641–42. http://dx.doi.org/10.1016/s0008-6223(99)00161-x.

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33

Kopylets', V. I. "Heats of adsorption of hydrogen on metals." Materials Science 35, no. 3 (1999): 438–41. http://dx.doi.org/10.1007/bf02355490.

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34

Builes, Santiago, Stanley I. Sandler, and Ruichang Xiong. "Isosteric Heats of Gas and Liquid Adsorption." Langmuir 29, no. 33 (2013): 10416–22. http://dx.doi.org/10.1021/la401035p.

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35

Sundaram, Narasimhan, and Ralph T. Yang. "Isosteric Heats of Adsorption from Gas Mixtures." Journal of Colloid and Interface Science 198, no. 2 (1998): 378–88. http://dx.doi.org/10.1006/jcis.1997.5300.

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36

Saha, Bidyut B., Shigeru Koyama, Ibrahim I. El-Sharkawy, Khairul Habib, Kandadai Srinivasan, and Pradip Dutta. "Evaluation of Adsorption Parameters and Heats of Adsorption through Desorption Measurements." Journal of Chemical & Engineering Data 52, no. 6 (2007): 2419–24. http://dx.doi.org/10.1021/je700369j.

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37

Dubinin, M. M., G. U. Rakhmatkariev, and A. A. Isirikyan. "Differential heats of adsorption and adsorption isotherms of alcohols on silicalite." Bulletin of the Academy of Sciences of the USSR Division of Chemical Science 38, no. 9 (1989): 1950–53. http://dx.doi.org/10.1007/bf00957798.

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38

Garcia-Cuello, V., J. C. Moreno-Piraján, L. Giraldo-Gutiérrez, K. Sapag, and G. Zgrablich. "Determination of Differential Enthalpy and Isotherm by Adsorption Calorimetry." Research Letters in Physical Chemistry 2008 (July 15, 2008): 1–4. http://dx.doi.org/10.1155/2008/127328.

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An adsorption microcalorimeter for the simultaneous determination of the differential heat of adsorption and the adsorption isotherm for gas-solid systems are designed, built, and tested. For this purpose, a Calvet heat-conducting microcalorimeter is developed and is connected to a gas volumetric unit built in stainless steel to record adsorption isotherms. The microcalorimeter is electrically calibrated to establish its sensitivity and reproducibility, obtaining K=154.34±0.23 WV−1. The adsorption microcalorimeter is used to obtain adsorption isotherms and the corresponding differential heats for the adsorption of CO2 on a reference solid, such as a NaZSM-5 type zeolite. Results for the behavior of this system are compared with those obtained with commercial equipment and with other studies in the literature.

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39

Zagorevskaya, E. V., N. V. Ishchenko, A. V. Kiselev, and N. V. Kovaleva. "Studies of adsorption of polychlorocarbons on carbon blacks by gas chromatography." Adsorption Science & Technology 2, no. 4 (1985): 219–28. http://dx.doi.org/10.1177/026361748500200402.

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Adsorption properties of carbon black before and after modification to polyhalogenohydrocarbons, including polyorganochlorine pesticides, have been investigated. It has been shown that graphitised thermal carbon blacks and carbochroms possess high adsorption capacity relative to the above compounds and can be used as supporting adsorbents to analyse these airborne chemicals. Modification raises the selectivity of adsorbents to the compounds being investigated and lowers retention volumes and heats of adsorption, which makes it possible to carry out thermal desorption of the accumulated species at lower temperatures.

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Bardina, I. A., E. V. Kalashnikova, N. V. Kovaleva, T. A. Rudnitskaya, and N. K. Shonya. "Adsorption Properties and Structure of Some Active Carbons." Adsorption Science & Technology 10, no. 1-4 (1993): 211–20. http://dx.doi.org/10.1177/0263617499010001-420.

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Gas chromatography has been used to determine the initial low-coverage heats of adsorption of C2–C6 hydrocarbons and their derivatives on active carbon and graphitized carbon black. The porous structure of the active carbon has been determined from the adsorption isotherms of benzene measured at 25°C by a vacuum static method. The isotherms have been analyzed with the help of the BET and Dubinin–Radushkevich theories.

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Rossi, Pier Francesco, та Paola Rossi. "Heats of Adsorption of Aliphatic Alcohols on α-Al2O3 at 25–200°C. II. Variations with Chain Length". Adsorption Science & Technology 15, № 1 (1997): 69–77. http://dx.doi.org/10.1177/026361749701500107.

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The adsorption of the first five members of the aliphatic alcohol series on α-Al2O3 has been studied at 25–200°C by means of a heat-flow Calvet microcalorimeter (moderately high temperature). At very low coverage and at 25°C, the values of the differential heats of adsorption of the different alcohols were very high (250–200 kJ/mol) and were apparently independent of the chain length. However, at average coverage, the chain length of the alcohol began to influence both the values and the trends in the differential heats of adsorption of the various alcohols on α-Al2O3. Finally, at high coverage, it was found that the incorporation of each additional –CH2–group in the homologous series led to a decrease in both the integral heat of adsorption and the amount of alcohol adsorbed according to the series MeOH > EtOH > 1-PrOH > 1-BuOH > 1-PeOH. Increasing the temperature led to an increasing dependence of the differential heat on the chain length of the alcohol. In addition, from measurements of the thermokinetic parameters for the heat emission peaks for the adsorbed alcohols, it has been deduced that all five aliphatic alcohols studied adsorb on to an α-Al2O3 surface in an open-chain perpendicular fashion.

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42

Rossi, P. F. "Adsorption Heat-Flow Microcalorimetry Applied to Coal Surface Properties." Adsorption Science & Technology 9, no. 3 (1992): 148–89. http://dx.doi.org/10.1177/026361749200900303.

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An account is given of the various forces involved in the adsorption of gases and vapours at a solid surface. The heat evolved during such processes may be measured by means of a microcalorimeter such as that designed by Calvet, whose description and application is discussed in detail. The use of such a microcalorimeter in studying adsorption at coal surfaces is described where differences in the measured differential heats of adsorption may be attributed either to the residual mineral content of the coal and/or to oxidation by air during its pretreatment.

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Cascarini de Torre, L. E., J. L. Llanos, and E. J. Bottani. "Nitrogen cross-sectional area on standard graphite." Collection of Czechoslovak Chemical Communications 53, no. 2 (1988): 251–57. http://dx.doi.org/10.1135/cccc19880251.

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Nitrogen physical adsorption at 77.5 and 80.4 K on a standard graphite was studied with the purpose too analyze adsorption models and to determine nitrogen cross-sectional areas for each model. With this intention different models, such as Van der Waals, Langmuir, and BET, which describe the adsorption process at different surface coverages were employed. Molar differential entropies and isosteric heats of adsorption were calculated. A two-dimensional phase transition was confirmed. Adsorbed molecule cross-sectional areas were determined at different surface coverages, by direct comparison with that corresponding to argon. The values obtained varied in a wide range (0.135 to 0.166 nm2) depending on surface coverage.

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Awadallah-F, Ahmed, Febrian Hillman, Shaheen A. Al-Muhtaseb, and Hae-Kwon Jeong. "Adsorption of Carbon Dioxide, Methane, and Nitrogen Gases onto ZIF Compounds with Zinc, Cobalt, and Zinc/Cobalt Metal Centers." Journal of Nanomaterials 2019 (December 23, 2019): 1–11. http://dx.doi.org/10.1155/2019/6130152.

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ZIF-8, Co-ZIF-8, and Zn/Co-ZIF-8 are utilized in adsorbing nitrogen (N2), methane (CH4), and carbon dioxide (CO2) gases at temperatures between 25 and 55°C and pressures up to ~1 MPa. Equilibrium adsorption isotherms and adsorption kinetics are studied. The dual-site Langmuir equation is employed to correlate the nonisothermal adsorption equilibrium behavior. Generally, N2 showed the lowest equilibrium adsorption quantity on the three samples, whereas CO2 showed the highest equilibrium adsorption capacity. Amid the ZIF samples, the biggest adsorption quantities of N2 and CH4 were onto Zn/Co-ZIF-8, whereas the highest adsorption quantity of CO2 was on ZIF-8. The isosteric heats of adsorbing these gases on ZIF-8, Co-ZIF-8, and Zn/Co-ZIF-8 were examined. Moreover, the overall mass transfer coefficients of adsorption at different temperatures were investigated.

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45

Goss, Kai-Uwe, and René P. Schwarzenbach. "Empirical Prediction of Heats of Vaporization and Heats of Adsorption of Organic Compounds." Environmental Science & Technology 33, no. 19 (1999): 3390–93. http://dx.doi.org/10.1021/es980812j.

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Woodbury, George W., and Leo A. Noll. "Heats of adsorption from flow calorimetry: Relationships between heats measured by different methods." Colloids and Surfaces 28 (January 1987): 233–45. http://dx.doi.org/10.1016/0166-6622(87)80187-7.

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Gorchev, V. F., S. A. Karakhim, P. F. Zhuk, and V. V. Goncharuk. "Relation between adsorption coefficients and heats of adsorption on a nonuniform surface." Theoretical and Experimental Chemistry 30, no. 5 (1995): 227–29. http://dx.doi.org/10.1007/bf00536694.

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48

Dios Cancela, G., F. J. Huertas, E. Romero Taboada, F. Sánchez-Rasero, and A. Hernández Laguna. "Adsorption of Water Vapor by Homoionic Montmorillonites. Heats of Adsorption and Desorption." Journal of Colloid and Interface Science 185, no. 2 (1997): 343–54. http://dx.doi.org/10.1006/jcis.1996.4572.

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Wang, Yutong, Xu Jiang, Xiong Yang, et al. "Molecular Simulation of Adsorption Separation of CO2 from Combustion Exhaust Mixture of Commercial Zeolites." Processes 11, no. 10 (2023): 2987. http://dx.doi.org/10.3390/pr11102987.

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The adsorption thermodynamics and kinetics of CO2 and six combustion products (H2O, SO2, N2, O2, NO and NO2) of two most commonly used commercial zeolites (13X and 5A) were studied based on validated molecular simulations. Adsorption isotherms at wide range of temperatures (253–333 K) were fitted by a Langmuir model, obtaining equilibrium parameters including the adsorption capacity, strength, heterogeneity and CO2 selectivity from the mixture. The diffusion coefficients, isosteric adsorption heats and distributions of potential energy were simulated for further explanation. The comprehensive evaluation results suggest that, in actual combustion product mixtures, the presence of H2O in combustion products has a significant impact on CO2 capture efficiency. Under the influence of water, the adsorption capacity of CO2 was reduced by over 80%.

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Shek, C. H., and G. M. Lin. "Thermal analysis studies of oxygen chemisorption on nanocrystalline SnO2." Journal of Materials Research 15, no. 9 (2000): 1994–97. http://dx.doi.org/10.1557/jmr.2000.0286.

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The oxygen chemisorption on nanocrystalline SnO2 at temperature range between 100 and 450 °C was studied with differential thermal analysis (DTA) and electrical conductivity measurement. The O2−, O−, and O2m ionosorptions were observed and could be distinguished from each other only on nanocrystalline SnO2 with grain size less than 5 nm. Assuming steady-state adsorption, the heats of adsorption for O2− and O− (or O2−) on nanocrystalline SnO2 are 1.09 and 1.50 eV respectively from the results of DTA.

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