A comprehensive modeling investigation of hydrogen sulfide absorption by Deep Eutectic Solvents

Abstract

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.