A multiscale investigation combining thermodynamic modeling and molecular dynamics study on CO2 capture with [N1111][Triz]-H2O solvent

Abstract

The urgent need to mitigate anthropogenic CO₂ emissions has driven the development of energy-efficient carbon capture systems. This study investigated a [N₁₁₁₁][Triz]-H₂O hybrid solvent for CO₂ capture using integrated experimental and computational approaches. A multiscale methodology combining thermodynamic analysis, phase equilibrium measurements, and molecular dynamics (MD) simulations was employed to elucidate the absorption mechanisms and the composition-property relationships. The thermodynamic analysis, incorporating Henry's law, the non-random two-liquid (NRTL) model for activity coefficients, the Redlich-Kwong equation, and reaction equilibrium constraints, accurately predicted the gas-liquid equilibrium (GLE) behavior, achieving an R² of 99.1% and an average absolute relative deviation (AARD) of 7.76%. The [N₁₁₁₁][Triz]-H₂O hybrid solvent exhibits exceptional CO₂ absorption performance, with a capacity of 0.25 mol/mol (at 313.15 K and 0.025 MPa for w_IL = 80%), attributed to synergistic physical-chemical interactions. MD simulations reveal the dynamic CO₂ absorption process in [N₁₁₁₁][Triz]-H₂O hybrid solvents: CO₂ molecules preferentially accumulate at the gas-liquid interface before gradually diffusing into the bulk phase. Increasing the [N₁₁₁₁][Triz] content enhances CO₂ absorption capacity by providing more interaction sites, while water modulates interfacial behavior and diffusion kinetics. This research provides in-depth insights into the absorption behaviors of [N₁₁₁₁][Triz]-H₂O hybrid solvents for CO₂, offering theoretical support for the development of efficient CO₂ capture solvents and highlighting its potential for industrial implementation.