Enthalpy Effects Research Articles

Lapachol, a natural food component, interacts with human serum albumin: Insights of its impact on the pharmacokinetics of clinically used drugs

Lapachol (LAP), a natural 1,4-naphthoquinone used in popular medicine of South American, is an antioxidant and antimicrobial compound used as a food additive; however, its interactive profile with the main protein carrier of compounds in the human bloodstream (human serum albumin, HSA) was not still characterized. Additionally, the impact of LAP in binding clinically drugs to albumin is still unknown. Thus, the present work describes the interaction HSA:LAP using different biophysical techniques, i.e., 1H saturation-transfer difference nuclear magnetic resonance (1H STD-NMR), isothermal titration calorimetry (ITC), steady-state and time-resolved fluorescence measurements combined with molecular docking calculations. LAP interacts with subdomain region IIA (site I), mainly driven by enthalpy effects, while subdomain region IB (site III) was identified as the second binding site, mainly driven by entropy effects. The binding is spontaneous, strong (binding constant average, Kaverage ≈ 4.45 × 105 M−1), and there is a positive cooperativity in the presence of ibuprofen, with the LAP structure fully buried into the protein cavities. Overall, LAP might impact the residence time (pharmacokinetic profile) of drugs that bind to subdomains regions IIA and IB of albumin, e.g., warfarin, phenylbutazone, diflunisal, naproxen, camptothecin, doxorubicin, daunorubicin, suramin, and tyrosine kinase inhibitors.

CMAS Corrosion Behavior of Mid-Entropy Rare-Earth Hafnate (Y0.3Gd0.3Yb0.4)4Hf3O12 as Thermal Barrier Coating Candidate.

High-temperature CMAS corrosion has become a crucial factor inhibiting the further development of thermal barrier coatings (TBCs) because of the increasing service temperature of aero-engines. Herein, a novel mid-entropy rare-earth hafnate (Y0.3Gd0.3Yb0.4)4Hf3O12 (YGYbH) was prepared by ultrafast high-temperature sintering (UHS) technology, and its CMAS corrosion behavior and mechanism were investigated. During corrosion, the Ca2RE8(SiO4)6O2 apatite phase with a lower formation enthalpy and entropy-stabilized effect had a more intense tendency to be generated, which improves the density and stability of the reaction layer, hindering the further penetration of molten CMAS. Moreover, the significant lattice distortion caused by the rare-earth ions with different radii impeded the ionic diffusion, which delayed the CMAS corrosion reaction. In general, YGYbH, with excellent CMAS corrosion resistance, has the potential to serve as a next-generation TBC material.

Effect of different Ga species in Ga-ZSM-5 on dehydrogenation performance of cyclohexane to benzene

Ga-containing ZSM-5 can effectively promote the dehydrogenation process in the methanol-to-aromatics (MTA) process. However, the forms of gallium species are diversity. It remains elusive which active gallium species has the best dehydrogenation activity. The catalytic activity of dehydrogenation of eight different Ga species (GaH2+, GaO+, Ga2O22+, GaH2+, Ga(OH)2+, Ga(OH)2+, GaH(OH)+, Ga+) in Ga-ZSM-5 was investigated by using DFT calculations in the dehydrogenation of cyclohexane to produce benzene as a model reaction. The DFT results combined with microkinetic calculation results suggested that GaH2+, Ga(OH)2+ and Ga2O22+, especially Ga2O22+, are the most likely species responsible for dehydrogenation. Interaction forces between metal ions and reactants and reactant activation energies show an inverted volcano type relationship. Enthalpy and entropy effects analysis indicate that the dehydrogenation of cyclohexane to benzene on Ga species is dominated by the enthalpy barrier. This opens up the prospect of better understanding the effect of dehydrogenating active species in Ga-doped ZSM-5 on the catalytic reaction.

Performance of anhydrous ethanol and gasoline blends on a SI engine: Decoupling evaporation enthalpy and knock resistance

Blending bioethanol with gasoline is recognized as a rapid solution for mitigating nonrenewable carbon dioxide emissions. This approach proves particularly meaningful in markets where the production of this biofuel aligns with sustainable practices. Understanding the alterations in the combustion process holds significance within these markets, contributing to informed decision-making and fostering environmentally conscious practices. In this context, it is widely known that highly ethanol blended fuels can provide benefits regarding suppression of knocking combustion in spark ignited engines if the quality of the base-fuel is not deteriorated to maintain octane ratings. However, the results of engine knocking investigations can be affected by two effects simultaneously. Firstly, ethanol has a beneficial effect on knock suppression due to its high enthalpy of evaporation compared to gasoline, which results in inner mixture cooling especially with direct injection. Secondly, ethanol can have beneficial effects on knock suppression by its decreased self-ignition tendency. This paper provides the set-up and results of an adapted engine testing procedure to diminish the effects of evaporation enthalpy during the knocking investigations of different highly ethanol blended fuels. The presented testing procedure at a single-cylinder research engine includes three technical steps: (1) the engine is equipped with a port fuel injection in stoichiometric operation for all tested fuels; (2) the engine is operated with constant speed of 1500 rpm and constant spark timing of 33° firing top dead center; (3) the engine is operated with fuel individual settings for the intake manifold gas pressure and intake manifold gas temperature. These parameters are adjusted to test all fuels with similar in-cylinder conditions at spark timing. The differing heating values of the fuels obviously result in differing engine loads. However, the presented testing procedure is aimed to achieve comparable in-cylinder conditions at spark timing without the effect of evaporation enthalpy. The novelty of the study lies in its adapted engine testing procedure that mitigates the cross-effects of fuel properties and operational conditions to isolate the true influences on knock occurrence. The paper provides a comprehensive description of the theoretical backgrounds, experimental set-up and post-processing procedures and also shows the results of the first measurement campaign.

Effect of Hofmeister Anions Series on the Langmuir Film of Tetronic 90R4 and Tetronic 701 Block Copolymers.

The air-water interfacial behavior of Tetronic 90R4 and Tetronic 701 was studied in the presence of sodium salts with different anions namely , , , , Cl-, Br-, , I-, and SCN-. Their presence in the subphase altered the arrangement of both tetronic molecules at the air-water interface. The limiting mean molecular area of the Langmuir film for both tetronics was found to be ion specific; it increased following the series < < < < Cl-< Br-< < I-< SCN-, which was found to be aligned with the Hofmeister series of anions. Furthermore, the study explored the effects of the hydration enthalpy, free energy, viscosity BJD coefficient, and polarizability of these anions on the interfacial behavior of tetronics. The Langmuir-Blodgett film morphology was also examined in the presence of these salt species using SEM. Morphologies were explained considering kosmotropic and chaotropic nature of these anions.

A novel heating system of solar-assisted enhanced jet enthalpy air source heat pump for cold regions

Solar energy and air source heat pumps are common heat sources for clean heating, but at lower ambient temperatures, the performance of solar energy and air source heat pumps will decline significantly, which can be ameliorated by integrating the two heat sources. However, the range of solar radiation and ambient temperature variation is very wide, and the existing integration methods cannot guarantee that they are optimal over a wide range. Therefore, this paper proposes a novel integration method of solar energy and jet enthalpy air source heat pump suitable for cold regions, where solar energy is used to heat the refrigerant in the jet branch to increase the flow rate of the jet branch, which enhances the effect of jet enthalpy. Under varying outdoor temperatures and solar radiations, the performances of the new integrated system and the traditional integrated systems are compared by simulation method. The results show that within the scope of this study (outdoor temperatures ranging from −30 °C to 10 °C, and radiations from 200 to 800 W/m2), the heat output and coefficient of performance of the new system are higher than those of the existing integrated systems. At an outdoor temperature of −30 °C and a radiation of 500 W/m2, the new system increases heat output by 45.8 % and coefficient of performance by 22.5 % compared with the existing two systems. This research can promote the application of solar energy and air source heat pump heating in cold regions.

Study on physicochemical properties of hydroxyl-functionalized ionic liquids

A thorough understanding of the physicochemical properties of ionic liquids (ILs) is significant for the design and synthesis of the desired ILs. In this study, three hydroxyl-functionalized ILs were designed and synthesized, and their density, viscosity, surface tension and refractive index were measured in the temperature range of 293.15–333.15 K, and it was found that they all decreased with the increase of temperature. By using the measured physicochemical property data and the corresponding empirical equations, the molecular volumes of the three ILs were calculated and the contribution of one (CH2-) group to the molecular volume was found to be 0.0262 nm3. The viscous flow activation properties were discussed and ΔH≠ > ΔS≠T was found for the three ILs, indicating that enthalpy effect is the main source of viscous flow resistance. Surface energy and surface entropy were calculated, and it was found that surface entropy is the main factor determining surface properties. The free volume was calculated, and it was found to increase with temperature, which could provide more space for light to pass through the medium, leading to a decrease in refractive index with temperature. Simultaneously, the influence of cation and anion structures on the properties of the ILs was also discussed.

Spray-Flame Synthesis of NASICON-Type Rhombohedral (α) Li1+xYxZr2-x(PO4)3 [x = 0-0.2] Solid Electrolytes.

Since solid electrolytes have a broad electrochemical stability window, are exceptionally electrochemically stable against Li metal, and function as a physical separator to prevent dendrite growth, they are at the forefront of alternate possibilities, further increasing the stability and energy density of Li-ion batteries. NASICON-type electrolytes are a promising candidate due to their negligible moisture sensitivity, which results in outstanding stability and a lower probability of Li2CO3 passivity under the ambient atmosphere. However, one of the most promising representatives, Li1+xYxZr2-x(PO4)3 (LYZP), has multiple stable phases with significant variation in their corresponding Li-ion conductivity. In this paper, we have successfully synthesized the highly ionically conductive rhombohedral phase of LYZP via spray-flame synthesis. Two different solvent mixtures (e.g., 2-ethyl hexanoic acid/ethanol, propanol/propanoic acid) were chosen to explore the effect of precursor composition and combustion enthalpy on the phase composition of the nanoparticle. The as-synthesized nanoparticles from spray-flame synthesis consisted of the crystalline tetragonal zirconia (t-ZrO2) phase, while lithium, yttrium, and phosphate were present on the nanoparticles' surface as amorphous phases. However, a short annealing step (1 h) was sufficient to obtain the NASICON phase. Moreover, we have shown the gradual phase conversion from orthorhombic β phase to rhombohedral α phase as the annealing temperature increased from 700 °C to 1300 °C (complete removal of β phase). In this context, Y3+ doping was also crucial, along with the appropriate solvent mixture and annealing temperature, for obtaining the much-desired rhombohedral α phase. Further, 0.2 at% Y3+ doping was added to the solvent mixture of 2-ethyl hexanoic acid/ethanol, and annealing at 1300 °C for 1 h resulted in a high ionic conductivity of 1.14∙10-5 S cm-1.

Computational prediction of MOFs with the potential to improve the efficiency of industrial CO2 capture

Capturing and storing carbon dioxide produced during industrial production operations has become a global focus in terms of energy conservation and emission reduction, especially for high-emission sources such as coal-fired power plants. In this study, the high-throughput Grand Canonical Monte Carlo (HT-GCMC) simulation method was used to assess the performance of 4,188 MOFs that were carefully selected from a comprehensive pool of 10,143 CoRE-MOFs using specific criteria. Exploratory data analysis for the population demonstratedthe effect of structural properties and isosteric enthalpy on MOFs’ adsorption performance. 90 MOFs were identified as superior adsorbents that show a strong adsorption performance when screening based on four filter criteria considered important for improving industrial economic efficiency. As the desorption pressure was increased, numerous MOFs maintained their potential and met the four screening conditions. This implies that there is room to increase the desorption pressure, which suggests a potential energy saving in practical applications. HT-GCMC was applied to calculate the adsorption properties of the 90 potential MOFs using various industrial CO2 concentration levels and showed the versatility of these MOFs for use in various industrial CO2 separation schemes. In addition, the adsorption mechanism of potential MOFs was analyzed, revealing specific numerical ranges for Qst and structural characteristics that correlate with their performance. Character analysis of 90 potential MOFs revealed that the elements O, N, Zn, and Cu have the highest content; C-O, Cu-O, C-N, and Cu-N are the bonded atom pairs most commonly seen in these 90 potential MOFs.

Microstructures and hydrogen evolution reaction performance of Ru-M(M=Cu, Ni and Nb) system by magnetron sputtering: The mixing enthalpy effect

Nanostructured hydrogen evolution reaction (HER) electrocatalysts were prepared by magnetron sputtering. With increasing sputtering power of the Ru target, the catalytic performance of Cu-Ru system improved. Pure Ru sample shows the best performance, due to the larger electrochemical surface area, better hydrophily and smaller electron transfer impedance. No Cu-Ru interaction to improve the catalytic property was observed. This can be attributed to the formation of Cu and Ru nanograins rather than CuRu alloys, due to the repulsive force between Ru and Cu resulted by the positive mixing enthalpy. For Ni-Ru system with a mixing enthalpy close to 0, nanocrystalline NiRu alloys formed. Ru1Ni3 showed a high HER performance close to pure Ru due to the synergistic effect. Nb-Ru also shows synergistic interaction to improve the HER performance. Though the active area is smaller than pure Ru, Nb1Ru1 sample achieves an overpotential of 39 mV at a current density of 10 mA/cm2, lower than that of pure Ru. The main reason can be attributed to the formation of amorphous/crystalline heterojunction due to the negative mixing enthalpy. This promotes the charge transfer at the interface, leading to a smaller electrochemical impedance. The Nb1Ru1 sample also shows better stability for 100 h test with an increasing of only 6 mV of the overpotential at 10 mA/cm2.

Hydroxide and Hydronium Ions Modulate the Dynamic Evolution of Nitrogen Nanobubbles in Water.

It has been widely recognized that the pH environment influences the nanobubble dynamics and hydroxide ions adsorbed on the surface may be responsible for the long-term survival of the nanobubbles. However, understanding the distribution of hydronium and hydroxide ions in the vicinity of a bulk nanobubble surface at a microscopic scale and the consequent impact of these ions on the nanobubble behavior remains a challenging endeavor. In this study, we carried out deep potential molecular dynamics simulations to explore the behavior of a nitrogen nanobubble under neutral, acidic, and alkaline conditions and the inherent mechanism, and we also conducted a theoretical thermodynamic and dynamic analysis to address constraints related to simulation duration. Our simulations and theoretical analyses demonstrate a trend of nanobubble dissolution similar to that observed experimentally, emphasizing the limited dissolution of bulk nanobubbles in alkaline conditions, where hydroxide ions tend to reside slightly farther from the nanobubble surface than hydronium ions, forming more stable hydrogen bond networks that shield the nanobubble from dissolution. In acidic conditions, the hydronium ions preferentially accumulating at the nanobubble surface in an orderly manner drive nanobubble dissolution to increase the entropy of the system, and the dissolved nitrogen molecules further strengthen the hydrogen bond networks of systems by providing a hydrophobic environment for hydronium ions, suggesting both entropy and enthalpy effects contribute to the instability of nanobubbles under acidic conditions. These results offer fresh insights into the double-layer distribution of hydroxide and hydronium near the nitrogen-water interface that influences the dynamic behavior of bulk nanobubbles.

Stagnation enthalpy effects on hypersonic turbulent compression corner flow at moderate Reynolds numbers

Stagnation enthalpy effects on hypersonic turbulent compression corner flow at moderate Reynolds numbers

Mixing entropy and enthalpy effects on europium ions in Eu-doped BaAl2O4

Distributions of Eu2+ and Eu3+ do affect the optical properties. However, the substitution of the activator ions hardly perturbed the crystal structure of the host lattice. Without the differences in crystal structure, it is not trivial to develop an effective descriptor to investigate stoichiometry-dependent mechanism to explore the effects of Eu species on valence states. In this study, through x-ray nanodiffraction, x-ray fluorescence, x-ray absorption near edge structure, and x-ray excited optical luminescence, we mapped the valence state distributions of Eu species to calculate the local mixing enthalpy and entropy. The calculated thermodynamics parameters show good agreement with the optical properties. We found that Eu2+ of Eu-doped BaAl2O4 predominantly existed in a divalent state, which results in segregation phenomena of local Eu2+ and Eu3+ ions.

Effect of steam quality on the oil recovery factor of the Karazhanbas field

Background: The injection of the thermal agent as "steam" reduces the viscosity of the oil and the mobility ratio, which increases the displacement and coverage factor, and ultimately significantly increases the oil recovery factor. This statement was the basis for determining the effect of steam enthalpy on the oil recovery factor, as well as for reliably determining the flow rate of flared gas, as a result of which the existing gas pipeline will be reconstructed, the required amount of fresh water will be calculated, and the distribution of steam pumping in the entire Karazhanbas field.&#x0D; Aim: The purpose of the article is to consider the influence of the quality of steam produced at the steam generator units of the Karazhanbas field on the oil recovery factor. The main parameter that determines the quality of steam is dryness, which was calculated using the actual values of the boiler (pressure, temperature, gas flow), flue gas tests on a special device, as well as laboratory tests to determine the heat value of the combusted gas.&#x0D; Materials and methods: This work used materials from GHM (geological and hydrodynamic modeling), results of studies of boiler flue gases and heat balance.&#x0D; Results: The calculation showed a low quality of the produced steam, which negatively affects the recovery factor.&#x0D; Conclusion: Evaluation to determine the optimal value of saturated steam parameters (steam dryness, temperature in terms of development efficiency) showed that the higher the temperature and dryness of steam at the wellhead and bottom hole of the injection well, the higher the oil recovery factor at the Karazhanbas field.

Predicting small molecules solubility on endpoint devices using deep ensemble neural networks.

Aqueous solubility is a valuable yet challenging property to predict. Computing solubility using first-principles methods requires accounting for the competing effects of entropy and enthalpy, resulting in long computations for relatively poor accuracy. Data-driven approaches, such as deep learning, offer improved accuracy and computational efficiency but typically lack uncertainty quantification. Additionally, ease of use remains a concern for any computational technique, resulting in the sustained popularity of group-based contribution methods. In this work, we addressed these problems with a deep learning model with predictive uncertainty that runs on a static website (without a server). This approach moves computing needs onto the website visitor without requiring installation, removing the need to pay for and maintain servers. Our model achieves satisfactory results in solubility prediction. Furthermore, we demonstrate how to create molecular property prediction models that balance uncertainty and ease of use. The code is available at https://github.com/ur-whitelab/mol.dev, and the model is useable at https://mol.dev.

Understanding the impact of ammonium ion substitutions on heterogeneous ice nucleation.

Understanding the mechanisms underpinning heterogeneous ice nucleation in the presence of ionic inclusions is important for fields such as cryopreservation and for improved models of climate and weather prediction. Feldspar and ammonium are both present in significant quantities in the atmosphere, and experimental evidence has shown that feldspar can nucleate ice from ammonium-containing solutions at temperatures warmer than water alone. In recent work, Whale hypothesised that this increase in nucleation temperature is due to an increase in configurational entropy when an ammonium ion is included in the ice hydrogen bond network (T. F. Whale, J. Chem. Phys., 2022, 156, 144503). In this work, we investigate the impact of the inclusion of an ammonium ion on the hydrogen bond network by direct enumeration of the number of structures found using Rick's algorithm. We also determine the energy of these systems and thus compare the effects of enthalpy and entropy to test Whale's hypothesis. We find that the inclusion of an ammonium ion increases the total number of configurations under conditions consistent with a realistic surface charge. We also find that the enthalpic contribution is dominant in determining the location of the ammonium ion within the structure, although we note that this neglects other practicalities of ice nucleation.

Study on self-healing mechanism of magnetic nano-powders functionalized fiber reinforced thermoplastic composites

At present, a variety of methods have been developed to realize the self-healing function of fiber-reinforced composites. However, the intrinsic mechanism of material damage recognition and self-healing initiation still lacks systematic research. In this paper, GF/(FeNip/PP) composites with multistage structures were prepared to study the self-healing properties and the mechanism of fiber-reinforced thermoplastic composites. The addition of a small amount of FeNip without affecting the melting peak temperature of the PP matrix (i.e., without reducing the use temperature of PP) can increase the electromagnetic loss (tanδ) of the composites by about 40% and the thermal conductivity by 36%. The cyclic stretching times of GF/(FeNip/PP) composites after microwave healing are doubled at 50% to 60%σmax load. It is indicated that FeNip endows the GF/PP composites with good microwave healing performance, and the purposeful repair can effectively extend the service life of the material. In addition, the self-healing mechanism of GF/(FeNip/PP) composites is discussed in detail from the aspects of microstructure change, multiphase interface effect, entropy enthalpy effect, starting and ending of self-healing procedures, etc. The magnetothermal effect, “entropy consumption” effect, and polymer chain diffusion are the fundamental reasons for the self-healing function of fiber reinforced thermoplastic composites.

A theoretical calculation and kinetic modeling analysis of H-abstraction from 1-octene for subsequent isomerization and [formula omitted]-dissociation

As a main component of alkenes, 1-octene is the key important intermediate in the process of oxidation or pyrolysis of n-decane or higher alkanes. In this work, quantum chemistry calculations of the 1-octene combustion and pyrolysis were illustrated for the potential energy surface, including the H-abstraction reactions and subsequent isomerization and β-dissociation reactions. The primary β-dissociation reactions after the H-abstraction reaction involving H atoms and CH3/NH2/NO2 radicals are detailed description with kinetic calculation. The rate constants of the primary pyrolysis reaction of 1-octene from 300 to 2000K were determined with the RRKM theory combined with CTST. The results indicated the H-abstraction reactions adhere to the Evans-Polanyi principle within the calculation uncertainty 1 kcal/mol. The 3-site exhibited the highest competitiveness in the 1-octene H-abstraction process and dominated, whereas the 1-site is lack of competitiveness due to overcome higher energy barriers (2–4 kcal/mol). The five-membered or six-membered ring in the H atom transfer process served as the most favorable structure for the isomerization reaction of 1-octenyl because of the lowest transition state energy. The dissociation channel for converting 1-octenyl to various octadienes and H atoms consumed the least 1-octenyl in the dissociation process. Following temperatures exceeding 570K, INT6 exhibits a preeminent 1-octenyl consumption ratio, attributed to the synergy between the enthalpy and entropy effects. The modified kinetic data of 1-octene H-abstraction reactions by four radicals and the subsequent isomerization and β-dissociation was expanded from 300 to 2000K, 0.01–100 atm. The modified model shows the better experimental prediction capabilities.

The thermoelectric performance in transition metal-doped PbS influenced by formation enthalpy

Transition metals have excellent valence electrical properties and unique electronic state distribution and are regarded as potential materials for improving thermoelectric performance. However, the impact of transition metals on thermoelectric materials is restricted to the solid solution limit and doping efficiency, reinforcing the shortcomings in systematic research. Here, thermoelectric properties of transition metal (Ti, V, Cr, Zr, Nb, Mo)-doped PbS are compared and analyzed systematically based on the formation enthalpy. The DFT calculation indicates that the doping (except Zr) leads to the bandgap expansion and the density of states distortion near the Fermi level, while the localization property of the latter results in an invalid resonance level. The formation enthalpy dominates the carrier concentration due to the opposite trend of carrier concentration and formation enthalpy. The formation enthalpy of Zr, Ti, and Nb doping is more negative than others, leading to the more significant optimization of carrier concentration. The Moss–Burstein effect promotes the bandgap expansion, leading to weaker bipolar effects for Zr, Ti, and Nb doping. Eventually, the thermoelectric performance for Ti, Zr, and Nb doping is superior to others at high temperature. The Hume-Rothery rule of the formation enthalpy supplementation is more suitable for the doping and alloying in thermoelectricity. Thermodynamic stability analysis based on the formation enthalpy contribute the PbS-based thermoelectric devices evaluation. The present finding demonstrates the significant effect of formation enthalpy on the thermoelectric properties of PbS and provides a useful avenue for the doping modification and thermodynamic stability analysis of other thermoelectric alloy materials.

Influence of temperature on non-exchange sorption of aromatic amino acids by anion exchanger AV-17-8

The equilibrium in thearomatic amino acid (tryptophan, phenylalanine, tyrosine and histidine) – anion exchanger AV-17-8 (Cl-) systems at different temperatures was investigated In order to identify the influence of both increased and decreased temperatures on the sorption equilibrium the temperature range was 277-343 K was studied. Sorption isotherms were obtained at 277, 293, and 343 K. The thermodynamic description of sorption systems was carried out using an approach based on the idea that the sorption process is stoichiometric. The integral and differential energy characteristics and the compensation effect between the enthalpy and entropy components for the studied sorption systems were calculated. A change in temperature led to a change in the physicochemical properties of the studied sorbates and sorbent. In the temperature range 277-243 K, the solvent content in the sorbent phase remained unchanged. A low solvent content at a temperature of 333 K and an increase in its amount at 343 K were experimentally established. It should be considered that at different temperatures the ionization constants of functional groups and the regions of existence of ionic forms of amino acids change, but the sorption mechanism does not change, since the recharging of amino acids did not occur. It was established that the process is exothermic for tryptophan and phenylalanine. With increasing temperature, the amount of sorbed substance decreased. The absorption energy was low due to the significant compensatory effect of enthalpy and entropy factors, the differential Gibbs energy was practically independent of temperature due to the stabilizing effect of hydrophobic forces in the sorbent phase. For the poorly soluble amino acid tyrosine, when the temperature increased from 277 to 293 K, a slight increase in sorption was observed, and with a further increase, a decrease to trace amounts was revealed. In the temperature range of 277-293 K, the sorption process was characterized by the formation of a supersaturated solution in the sorbent phase and was endothermic. The sorption of hydrophilic histidine increased with increasing temperature, which correlates with the solvent content in the sorbent phase, including low content at 333 K. The process of histidine sorption is endothermic, characterized by a strong dependence of the differential Gibbs energy on temperature and the absence of a compensation effect between the enthalpic and entropic components.