Integrated DFT Study of CO₂ Capture and Its Utilization in Gingerol Extraction Using Choline Chloride–Lactic Acid Deep Eutectic Solvent

Carbon dioxide (CO₂) emissions remain a pressing global concern due to their disproportionately large contribution to greenhouse-gas-driven climate change. CO₂ is released through multiple anthropogenic processes, including industrial activity, transportation, and residential energy use. To mitigate its environmental impact, sustainable carbon capture and utilization (CCU) strategies are essential—especially those that can transform captured CO₂ into valuable products. This study aimed to investigate, using Density Functional Theory (DFT), the potential of a choline chloride–lactic acid deep eutectic solvent (ChCl–Lac DES) to serve as a dual-function system for both CO₂ capture and gingerol extraction, contributing to green pharmaceutical applications. All calculations were performed using the wB97X-D functional with PM3-optimized geometries, employing a dual basis set in the gas phase to account for dispersion effects. The DES showed a significantly more negative CO₂ binding energy (–0.86 eV) compared to monoethanolamine (MEA, –0.234 eV), confirming superior CO₂ affinity. Additionally, CO₂ demonstrated moderate binding with 6-gingerol (–0.17 eV), supporting its viability in pharmaceutical extraction. Notably, the DES exhibited an even stronger interaction with 6-gingerol (–1.87 eV), highlighting its potential as a green extraction solvent following CO₂ capture. These findings confirm ChCl–Lac DES as a promising candidate for integrated CCU systems, enabling both carbon mitigation and value-added chemical recovery.