Understanding the performance of amine-based DESs for acidic gases capture from biogas

The current work presents comprehensive data derived from the thermophysical assessment of monoethanolamine (MEA)-based Deep Eutectic Solvents (DESs) for H2S extraction from biogas. The MEA-based DES demonstrated the capability to absorb H2S and CO2 from biogas at various pressures, as evidenced by density profile analysis. Analyses were made to determine the solubility of acidic gases and the solubility selectivity of H2S over CO2, H2S over CH4, and CO2 over CH4. According to the findings, MEA-based DES absorbed 40 %, 60 %, and 80 % of H2S concentration from biogas at pressures of 10 atm, 15 atm, and 20 atm, respectively. Structural analyses, including radial and spatial distribution functions, quantification of hydrogen bonds between DES species and acidic gases, and evaluation of non-bonded interaction energies, were explored to gain a more in-depth understanding of the absorption mechanism. Moreover, the diffusion coefficient of species after the absorption process reveals that CO2, with a diffusion coefficient of 556.5 Å2/ns, moves more quickly than H2S, which exhibited a value of 348.2 Å2/ns. According to our findings, the MEA-based DES is a highly effective choice for removing H2S from biogas.