Carbon dioxide solubility in choline chloride-based deep eutectic solvents under diverse conditions

Area of Science:

• Computational Chemistry
• Materials Science
• Environmental Science

Background:

• Global warming, driven by rising CO2 emissions, necessitates effective carbon capture solutions.
• Deep eutectic solvents (DESs) are emerging as promising absorbents for CO2 due to their stability and capacity.
• Understanding molecular-level properties of DESs is crucial for designing efficient CO2 capture systems.

Purpose of the Study:

• To investigate CO2 sorption and diffusion mechanisms in various DESs using molecular dynamics (MD) simulations.
• To analyze the influence of temperature and pressure on CO2 behavior within DESs.
• To determine the preferential location of CO2 molecules within the DES environment.

Main Methods:

• Molecular dynamics (MD) simulations were employed to model CO2 interactions within different DESs.
• Software used included PACKMOL for initial configurations, Gaussian 09 for geometry optimization, and NAMD for simulations.
• Spatial distribution functions were analyzed using TRAVIS software to understand CO2 localization.

Main Results:

• CO2 molecules exhibit preferential concentration at the CO2-DES interface.
• CO2 diffusion in bulk DES increases with rising temperature and pressure.
• CO2 solubility order at high pressure (58.6 bar) was determined as Choline Chloride-Ethylene Glycol < Choline Chloride-Urea < Choline Chloride-Glycerol.

Conclusions:

• MD simulations provide valuable molecular-level insights into CO2 behavior in DESs.
• The findings highlight the importance of interfacial effects and thermodynamic conditions for CO2 capture efficiency.
• Specific DES compositions demonstrate varying CO2 solubility, guiding the selection of optimal materials for carbon capture.