Computational analysis of CO2 capture through deep eutectic solvents and silver nanoparticles

Abstract

The high levels of greenhouse gas (GHG) emissions in the atmosphere, especially CO2, are driving global warming, which is causing several problems for society, such as droughts, hurricanes, heat waves, and floods. Therefore, it is urgent to capture CO2 gas. In this thesis, the first work analyzed the effect of increased temperature on CO2 absorption using a deep eutectic solvent (DES) based on urea and choline chloride (reline) through molecular dynamics (MD) simulations and non-covalent interactions (NCI). Posteriorly, the second work analyzed the synergistic effect of three DESs (ethaline, reline, and glyceline) and a silver nanoparticle (AgNP) in the CO2 capture process through MD simulations. In the first work, it was observed that the increased temperature effect occasioned the reduction of the hydrogen bond (HB) number between the CO2 molecules and the urea molecules, resulting in the highest total interaction potential energy (IPE), indicating that the CO2 absorption process is more indicated at 303 K, with an average IPE value of -3872.54 kJ mol-1. On the other hand, the NCI results indicated that the increased temperature effect resulted in increased repulsion interactions and reduced the strong interactions in the systems simulated. Therefore, both computational approaches suggested that the CO2 absorption process is more indicated at the temperature of 303 K. In the second work, it was registered that the AgNP presence increases the HB number between the CO2 gas and the molecules that act as hydrogen bond donors (HBD), resulting in the lowest total IPE values for this group, occasioning a better CO2 capture process, especially for the AgNP-reline-CO2 system, with an average IPE value of -757.68 kJ mol 1. The radial distribution function (RDF) analysis indicated that ethylene glycol and urea are key species in the CO2 capture process for the AgNP-ethaline-CO2 and AgNP-reline CO2 systems, respectively. Furthermore, the AgNP is the key species in the CO2 capture process for the AgNP-glyceline-CO2 system.