Autor: |
Mishra R; School of Chemical Engineering, Oklahoma State University, 420 Engineering North, Stillwater, Oklahoma 74078, United States., Bhawnani R; Department of Chemical Engineering, University of Illinois at Chicago, 929 W. Taylor St., Chicago, Illinois 60607, United States., Sartape R; Department of Chemical Engineering, University of Illinois at Chicago, 929 W. Taylor St., Chicago, Illinois 60607, United States., Chauhan R; Department of Chemical Engineering, University of Illinois at Chicago, 929 W. Taylor St., Chicago, Illinois 60607, United States., Thorat AS; School of Chemical Engineering, Oklahoma State University, 420 Engineering North, Stillwater, Oklahoma 74078, United States., Singh MR; Department of Chemical Engineering, University of Illinois at Chicago, 929 W. Taylor St., Chicago, Illinois 60607, United States., Shah JK; School of Chemical Engineering, Oklahoma State University, 420 Engineering North, Stillwater, Oklahoma 74078, United States. |
Abstrakt: |
Recent research and reviews on CO 2 capture methods, along with advancements in industry, have highlighted high costs and energy-intensive nature as the primary limitations of conventional direct air capture and storage (DACS) methods. In response to these challenges, deep eutectic solvents (DESs) have emerged as promising absorbents due to their scalability, selectivity, and lower environmental impact compared to other absorbents. However, the molecular origins of their enhanced thermal stability and selectivity for DAC applications have not been explored before. Therefore, the current study focuses on a comprehensive investigation into the molecular interactions within an alkaline DES composed of potassium hydroxide (KOH) and ethylene glycol (EG). Combining Fourier transform infrared (FT-IR) and quantum chemical calculations, the study reports structural changes and intermolecular interactions induced in EG upon addition of KOH and its implications on CO 2 capture. Experimental and computational spectroscopic studies confirm the presence of noncovalent interactions (hydrogen bonds) within both EG and the KOH-EG system and point to the aggregation of ions at higher KOH concentrations. Additionally, molecular electrostatic potential (MESP) surface analysis, natural bond orbital (NBO) analysis, quantum theory of atoms-in-molecules (QTAIM) analysis, and reduced density gradient-noncovalent interaction (RDG-NCI) plot analysis elucidate changes in polarizability, charge distribution, hydrogen bond types, noncovalent interactions, and interaction strengths, respectively. Evaluation of explicit and hybrid models assesses their effectiveness in representing intermolecular interactions. This research enhances our understanding of molecular interactions in the KOH-EG system, which are essential for both the absorption and desorption of CO 2 . The study also aids in predicting and selecting DES components, optimizing their ratios with salts, and fine-tuning the properties of similar solvents and salts for enhanced CO 2 capture efficiency. |