•A new extended thermodynamic model was developed for CO2 absorption in aqueous 2-dimethylamino-2-methyl-1-propanol solution.•The CO2 equilibrium solubility was investigated at different temperatures ...with various CO2 partial pressures.•The CO2 absorption heat was evaluated in aqueous 2-dimethylamino-2-methyl-1-propanol solution.
In this work, CO2 equilibrium solubility in aqueous 2-(dimethylamino)-2-methyl-1-propanol (2DMA2M1P) solution was investigated by varying temperature, CO2 partial pressure and amine concentration. Dissociation constant (pKa) and CO2 absorption heat of 2DMA2M1P were calculated. Results show that the CO2 equilibrium solubility increases with the CO2 partial pressure but decreases with the increase of temperature. It was also revealed that the CO2 equilibrium solubility declines when the concentration of 2DMA2M1P increases from 1 to 2 mol/L. In addition, a new extended Cf model was proposed for predicting the CO2 equilibrium solubility, and the predicted results show a good agreement with the experimental measured data with an average absolute deviation (AAD) of 2.08%. Furthermore, the proposed model was validated with the published data of tertiary amines, and the results indicate that the developed model has a good universality in predicting the CO2 equilibrium solubility. Finally, a comparison with other reported amines was also made in terms of the CO2 equilibrium solubility and the CO2 absorption heat. All of them proved that the 2DMA2M1P could be a competitive amine solvents for CO2 capture.
In this work, CO2 equilibrium solubility of 1M N,N‐diethylethanolamine (DEEA):2M 1,6‐hexamethyl diamine (HMDA), 1.5M DEEA:1.5M HMDA and 2M DEEA:1M HMDA was studied with a temperature range of 298–333 ...K and CO2 partial pressure range of 8–100 kPa. Seven thermodynamic models including Empirical model, Kent and Eisenberg (KE) model, Hu–Chakma model, Austgen model, Helei Liu model, Liu et al. model, and Li–Shen model were developed by correlating reaction equilibrium constants with observed equilibrium solubility of CO2 in mixed amine solvents. The evaluation of those models was conducted in terms of the average absolute relative deviation (AARD). The results indicated that Liu et al. model considering T, Amine, Ptotal and CO2(aq) can better represent this complex system with an AARD of 8.06%. Meanwhile, comprehensive comparison and analysis were also performed to identify the contribution of parameters to develop models, which could provide a guideline for the development of accurate thermodynamic models for representation of thermodynamic behaviors.
Main Species of aqueous Solution of DMAE and EAE- CO2 loading at T=313.15K; symbols; ♦: DMAEH+; ×: HCO−3; ■: DMAE; △: EAECOO−; ▲: CO2−3; +: CO2; ○: EAE.
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•Equilibrium solubility of ...carbon dioxide in aqueous amine mixtures solutions of N-Dimethylaminoethanol (DMAE) and 2-(Ethylamino)Ethanol (EAE) was measured in temperature range of 313.15–358.15 K and pressure range of 6.5–236 kPa.•The total amine concentrations of the solutions have been fixed equal to 45 %wt (DMAE 40 wt% + EAE 5 wt%) and 35% (DMAE 30 wt% + EAE 5 wt%).•The solubility data of CO2 in quaternary aqueous mixture of N-Dimethylaminoethanol and 2-(Ethylamino)Ethanol were correlated by the Deshmukh-Mather model with AAD% = 11.6% and 6.7% for (DMAE 40 wt% + EAE 5 wt%) and (DMAE 30 wt% + EAE 5 wt%), respectively.•The enthalpy of absorption CO2 in aqueous solution of (DMAE 40 wt% + EAE 5 wt%) was measured at T = 328.15 K and was predicted by the tunned Deshmukh-Mather model. The obtained AAD% was 24.0.
The equilibrium carbon dioxide solubility in aqueous solutions of N-dimethylaminoethanol (DMAE) 40 wt% + 2-(ethylamino) ethanol (EAE) 5 wt% and DMAE 30 wt% + EAE 5 wt% was measured at various temperatures (313.15, 328.15, 343.15, 358.15 K) in the range of pressures from 6.5 to 236 kPa. The enthalpy of absorption of carbon dioxide was measured for the mixture of DMAE (40 wt%) + EAE (5 wt%), at 328.15 K. The Deshmukh-Mather model was used to correlate the equilibrium solubility of carbon dioxide data, and the model parameters were optimized. The optimized model could correlate the vapor-liquid equilibrium with the 9.4 average absolute percentage deviation (AAD%), and the obtained AAD% for enthalpy of absorption in aqueous solution of DMAE (40 wt%) + EAE (5 wt%) was 24.0.
•Research the solubility of Glibenclamide in binary mixed solvents of methanol + water, n-propanol + water, isopropanol + water, and acetonitrile + water.•Extended Hildebrand Solubility Approach was ...applied to explain co-solvence phenomenon.•The solubility data were correlated by some thermodynamic models.•Some apparent thermodynamic properties were evaluated.
Equilibrium solubility of glibenclamide (GCM) in aqueous solutions of methanol, n-propanol, isopropanol, and acetonitrile were studied by static technique at temperatures ranging from 288.15 K to 323.15 K under p = 101.3 kPa. When the composition of cosolvent was constant in the four mixed solvents, GCM solubility increased with the rising temperature. When the temperature was fixed, the GCM mole fraction solubility showed positive dependence on the increasing mass fraction of methanol in methanol + water mixture. While in solutions of n-propanol + water, isopropanol + water, and acetonitrile + water, it first increased as the mass fraction of cosolvent (w) added, at around w = 0.9, the solubility reached a maximum value and then it descended. Thermodynamic models like Jouyban−Acree model, modified Apelblat−Jouyban−Acree model, and CNIBS/R-K model were taken to correlate the equilibrium mole fraction solubility of GCM in four solvent mixtures. The maximum RAD and the RMSD values calculated by the CNIBS/R-K model were found in the mixture of methanol + water and didn’t exceeded 7.4 × 10−2 and 1.48 × 10−5, respectively. However, the maximum RAD values obtained by the Jouyban−Acree and modified Apelblat−Jouyban−Acree model were found in the mixture of acetonitrile + water and didn’t exceeded 5.57 × 10−2 and 5.55 × 10−2, respectively. The RMSD all didn’t exceeded 2.54 × 10−5. Hence, the Jouyban−Acree model and modified Apelblat−Jouyban−Acree model are shown to be superior to the CNIBS/R-K model in this work. The experimental data and model parameters obtained will be helpful for the preparation and purification of GCM.
Introduction:In the coming decades, addressing climate change necessitates substantial Carbon dioxide (CO2) emission reductions. Carbon capture and storage are vital for achieving these goals. ...Beyond industrial emissions, Direct Air Capture (DAC) extracts CO2 from the atmosphere, complementing point source capture and enabling the reduction of atmospheric CO2 concentrations. Our research confirms the thermodynamic feasibility of DAC with Potassium hydroxide (KOH) solution, taking into account energy and performance considerations.
Materials and methods: To assess DAC's potential, we built a 1.2 m contactor prototype measuring CO2 absorption from the air. Operating at 100 pa with an air speed of 1.75 m/s in a cross-flow regime, we used KOH and NaOH solutions as capture mediums, implementing duty cycles for absorbent pumping and exhaust fan operation.
Results: Our findings revealed that transitioning to intermittent operation can dramatically reduce overall energy costs by 70%. We explored various absorbent concentrations for both KOH and NaOH solutions, examining their impact. Operating temperatures ranged from 14°C to 33°C, providing insights into temperature's pivotal role in DAC performance.
Conclusion: This study showcases the viability of DAC with a KOH solution, particularly highlighting the significant energy savings achieved through intermittent operation. These findings emphasise DAC's role as a vital tool in our collective efforts to combat climate change.
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•Solubility of sulfabenzamide in ScCO2 was measured for the first time.•Experiments were conducted on temperatures (308–338 K) and pressures (120–270 bar).•Solubility data were ...correlated by six density-based models (Sodeifian model with the lowest AARD% = 8.24).•A new thermodynamic model was developed and evaluated.•Thermodynamic enthalpies of sulfabenzamide were estimated.
Equilibrium solubilities of sulfabenzamide compound in supercritical carbon dioxide (ScCO2) have been explored at various pressures and temperatures. Solubilities measurements were carried using an equilibrium cell. Solubilities of sulfabenzamide reported were at four temperatures and at six pressures between (308 and 338) K and (12 and 27) MPa. The observed equilibrium solubilities were (1.53×10−6 to 6.15×10−6 at 308 K, 2.87×10−6 to 8.98×10−6 at 318 K, 6.15×10−6 to 13.61×10−6 at 328 K and 7.95×10−6 to 22.35×10−6 at 338 K). The measured saturation solubilities have been modeled with two new thermodynamic models based on solid–liquid equilibrium criteria. Moreover, Peng-Robinson’s equation of state (PREoS) with Van der Walls mixing rules (VdWmr) and few other empirical solubility models have been explored. PREoS as temperature independent and Sodefian et al., models are quite good in predicting the data. From the correlation results it is clear that PREoS as temperature independent is able to correlate the data below 8.59% (corresponding AICc is −660.82). Among empirical models Sodefian et al., model is able to correlate the data below 8.24% (corresponding AICc is −640.24).
•Ethyl group is beneficial for tertiary amines of CO2 absorption.•The existence of side carbon chain may promote the activity of tertiary amine.•Hydroxyl group reduces the equilibrium CO2 solubility, ...k2 and pKa.•Heterocyclic structure decrease the equilibrium CO2 solubility, k2 and pKa.•Hydroxyl group results in higher CO2 absorption heat.
This work examined the relationship between the structure of various commercial tertiary amines and their activity in CO2 absorption/desorption in terms of rate of CO2 absorption, equilibrium CO2 loading, pKa and heat of CO2 absorption in order to establish possible guidelines for selection of tertiary amine components for amine blends. Results show that any electron donating group linked directly to the nitrogen atom increases their reactivity with CO2. In addition, the presence of steric hindrance effect and good water solubility also show enhancements in activity. In contrast, the existence of a hydroxyl group leads to a decrease in all the activity of the tertiary amine. The heat of CO2 absorption of tertiary amines, which is closely related to the regeneration energy, can be reduced by decreasing the number of hydroxyethyl groups or by positing the hydroxyl group at the proper carbon relative to the nitrogen atom.
•The equilibrium CO2 solubility of EMAB with designed structures was measured.•The pKa, reaction kinetics, and heat of CO2 absorption of EMAB were evaluated.•Two novel models, i.e. Fugacity-activity ...and Extended Cf model, are established.•EMAB is a potential CO2 capture agent for use in amine-based PCC technology.
The aim of this project was to develop a thermodynamic model for the vapour-liquid equilibrium of an amine-water-carbon dioxide system and to evaluate the CO2 capture performance of aqueous EMAB solution. The structurally modified tertiary amine 4-(ethyl-methyl-amino)-2-butanol (EMAB) was chosen because of its molecular structure-activity relationship. Measurements were made of its equilibrium CO2 solubility, viscosity, dissociation constant, and second-order reaction rate constant, and the heat of absorption was then calculated. Additionally, the novel semi empirical model (Extended Cf model) and the novel rigorous thermodynamic model (fugacity-activity model) which take into consideration the association of the partial molar property and the equation of state were developed to predict the equilibrium CO2 solubility. The models can provide reasonable prediction results with AARDs of 2.3% and 3.68%, respectively. Furthermore, the thermodynamic and dynamic properties of EMAB were analyzed and evaluated by a comprehensive method and compared with some new tertiary amines and traditional commercial amines. The study concludes that EMAB has good CO2 capture performance and is expected to be one of the most promising alternative amines for post combustion CO2 capture technology.
The significance of thermodynamic solubility in biopharmaceutical compound or drug characterization as well as the importance of having methods that accurately establish it have been extensively ...addressed. Nonetheless, its precise determination continues to remain a challenging task to accomplish. Even more so when the number of compounds to evaluate is high and the available amount of each compound is low, both of which are inevitable for the compound characterization during the drug development process. Except for the shake-flask method which is still considered as the 'gold standard' in obtaining thermodynamic data, it is currently difficult to say that another satisfactory model which is routinely used to determine thermodynamic solubility is being applied. Therefore, this review summarizes the various experimental approaches which are based on the classical shake flask method but have yet attempted to speed up the experimental process of obtaining such data more conveniently. The most important experimental features of these approaches are provided to the reader. Some advantages and disadvantages associated with each approach are also highlighted, consequently offering a resource to those looking for the most appropriate of the approaches that have already fared well at determining the biopharmaceutically relevant drug solubility.
•The absorption capacities and the initial absorption rates have were measured in a stirred cell.•IL promotes CO2 absorption/desorption performance.•Reusability and performance were investigated by ...using FTIR under sequential absorption/desorption cycles.•Blends of ILs with MEA in 1-hexanol can be a potentially alternative solvent for CO2capture.
Blends of ionic liquids (ILs) with monoethanolamine (MEA) in 1-hexanol were employed to enhance CO2 removal in comparison with that of pure MEA. A series of hydrophobic and hydrophilic 1-alkyl-3-methylimidazolium-based ionic liquids (Cn-mimAc, Cn-mimCl, and Cn-mimTf2N with n = 2 or 4) were studied to investigate the absorption/desorption performance, which is known to be affected by changes in the type of anion used and the alkyl chain length in the cation. Three different weight percentages of ILs were added to 20 wt% MEA, and the maximum amine concentration in the liquid was obtained as 30 wt/wt%. The absorption capacity (or equilibrium solubility) was noted to be highly dependent on the selection of the anion, whereas the choice of cation had a minor effect. The results revealed that the addition of IL significantly improved the CO2 capture performance, and indicated a favorable loading ratio. The bmimAc IL was found to result in the highest CO2 equilibrium loading (0.89 mol CO2/(mol bmimAc)) compared to that in other blends. Moreover, the interactions between CO2 and the blend systems were characterized using Fourier transform infrared spectrometry (FTIR) to analyze the reusability and potential performance losses of the solvent systems.
