Articles
Publication Date: 2026
Industrial and Engineering Chemistry Research (15205045)65(1)pp. 917-928
Nowadays, deep eutectic solvents (DESs) are being investigated as environmentally friendly alternatives to traditional solvents. The solubility of methane in a DES plays a fundamental role in determining the overall methane/CO2 separation efficiency. Despite its significance, experimental data on methane solubility in DESs are limited. This study aims to experimentally determine the solubility of methane in a DES composed of 1 mol of NaCl and 16 mol of ethylene glycol using a high-pressure solubility apparatus. Solubility measurements were conducted at four isotherms, under pressures up to 3 MPa. For thermodynamic modeling, the Soave–Redlich–Kwong (SRK) equation of state (EoS) and the Peng–Robinson (PR) EoS were employed in conjunction with two mixing rules, namely, the conventional van der Waals (vdW) and the more advanced excess Gibbs energy mixing rules of Wong–Sandler (WS). Furthermore, the cubic plus association (CPA) EoS was applied in combination with the vdW mixing rules for thermodynamic modeling of methane in the investigated DES. Among all the thermodynamic packages, the combination of the PR EoS + WS mixing rules gave the best results with an average absolute relative deviation of 4.52%. Finally, Henry’s constant was determined from the experimental data, allowing for the subsequent calculation of the standard entropy, enthalpy, and Gibbs energy of the dissolution process. © 2026 American Chemical Society
Publication Date: 2025
Journal of Molecular Liquids (18733166)429
Natural gas is a valuable source of energy, however, it also contains hazardous compounds, such as hydrogen sulfide (H2S) acid gas, which needs to be eliminated to make it safe for use. If H2S is released, it can cause serious hazards like environmental issues and human respiratory or even death. Up to now, amine-based solvents have been used for gas sweetening. However, they are not environmentally friendly solvents, so replacing them with green solvents is required. Deep Eutectic Solvents (DESs) are the high-potential candidates of green solvents for this purpose. This study investigated comprehensive thermodynamic modeling of H2S solubilities in a wide range of different nature DESs using two thermodynamic approaches of φ-φ and γ-φ and one chemical absorption approach. The largest and most updated H2S solubility in DESs’ data bank was gathered from open literature including 338 data points for 33 different DESs over a wide range of temperature and pressure. For the investigated approaches, the SRK-SRK, SRK-NRTL, and RETM (1:2) models with the AARD% values of 13.42, 11.64, and 11.21, respectively led to the best results. According to comprehensive investigation and data analysis, general guidelines for using different thermodynamic models for H2S solubility in DESs were proposed. © 2025 Elsevier B.V.
Publication Date: 2025
Results in Engineering (25901230)27
The regulation of CO₂ emissions from industrial operations is crucial from an environmental perspective. The most widely used solvents for CO₂ capture consist of aqueous alkanolamine solutions. However, amine-based processes face several challenges, such as corrosion, chemical degradation, and high energy requirements for solvent regeneration. As potential alternatives, deep eutectic solvents (DESs) have emerged as promising eco-friendly and biodegradable options for CO₂ capture. This study experimentally measures the solubility of CO₂ in a DES (1 mol NaCl + 16 mol ethylene glycol) using a high-pressure solubility apparatus at the four temperatures of 293.15, 303.15, 313.15, and 323.15 K. For the thermodynamic modeling, the Soave Redlich Kwong equation of state (SRK EoS) was employed, coupled with three different mixing rules of van der Waals (vdW), Wong Sandler (WS), and modified Huron-Vidal (MHV1). The vdW approach was considered in the three cases without using binary interaction, constant binary interaction, and variable binary interaction parameter by temperature. The results demonstrated that by incorporating the WS and MHV1, the local composition concept was successful in addressing the non-ideality of the liquid phase. Among the tested models, the WS (AARD%=6.66) and MHV1 (AARD%=5.61) provided the most accurate predictions of equilibrium pressures. Additionally, Henry's constant, standard Gibbs energy, enthalpy, and entropy of gas solvation were determined using the experimental data together with classical thermodynamic relations. The calculated negative standard enthalpy of solvation indicates an exothermic gas solvation process, signifying that energy is released as CO₂ dissolves in this DES. © 2025
