Significant Improvement in CO₂ Absorption by Deep Eutectic Solvents as Immobilized Sorbents: Computational Analysis

Area of Science:

• Computational Chemistry
• Materials Science
• Chemical Engineering

Background:

• Deep eutectic solvents (DESs) offer potential for carbon dioxide (CO2) capture.
• Understanding the influence of solid supports and DES thickness on CO2 sorption is crucial for optimizing capture efficiency.

Purpose of the Study:

• To computationally investigate the efficacy of choline chloride-based DESs immobilized on solid surfaces for CO2 dissolution.
• To provide molecular-level insights into the role of DES thickness and solid support type on CO2 sorption and diffusion.

Main Methods:

• Molecular dynamics simulations were employed to study DES systems on graphite and titanium dioxide surfaces.
• Density profiles, distribution functions, orientational analysis, and mean-square displacements were used to analyze structural and dynamic properties.
• Density functional theory was utilized to determine effective interaction parameters for CO2 capture.

Main Results:

• CO2 molecules initially accumulate at the gas/DES interface, with diffusion into the bulk DES slowing as thickness increases.
• DESs supported on titanium dioxide exhibited higher CO2 absorption capacity than those on graphite.
• The study developed a model correlating CO2 solubility in choline chloride-based DESs with their immobilization on different supports.

Conclusions:

• The type of solid support significantly impacts CO2 absorption capacity, with hydrophilic TiO2 outperforming hydrophobic graphite.
• DES thickness influences CO2 diffusion dynamics, suggesting optimization strategies for enhanced capture.
• This research provides a quantitative molecular understanding for designing effective supported DES systems for CO2 capture.