Carbon Capture from Biogas by Deep Eutectic Solvents: A COSMO Study to Evaluate the Effect of Impurities on Solubility and Selectivity

Deep eutectic solvents (DES) are compounds of a hydrogen bond donor (HBD) and acceptor (HBA) that contain depressed melting point compared to their individual constituents. DES have been studied for use as carbon capture media biogas upgrading. However, contaminants’ presence in might affect the by DES. In this study, conductor-like screening model real (COSMO-RS) was used determine effect temperature, pressure, selective contaminants on five DES’ namely, choline chloride-urea, chloride-ethylene glycol, tetra butyl ammonium bromide-decanoic acid, octyl chloride-decanoic acid. Impurities paper sulfide, ammonia, water, nitrogen, octamethyltrisiloxane, decamethylcyclopentasiloxane. At infinite dilution, CO2 solubility dependence upon temperature each examined means Henry’s Law constants. Next, systems were modeled from dilution equilibrium using modified Raoults’ Law, where pressure examined. Finally, CH4 various explored with varying mole percent contaminants. Among parameters studied, it found HBD solvent is most determinant factor effectiveness solubility. Other factors affecting alkyl chain length HBA, associated halogen, resulting polarity It also chloride-urea CO2, but has lowest solubility, polar among other solvents. On hand, tetraoctylammonium acid least selective, highest maximum polar, affected its environment.