Aromatic VOCs absorption with phenyl–based deep eutectic solvents: A
molecular thermodynamics and dynamics study
Abstract
The suitability of phenyl–based deep eutectic solvents (DESs) as
absorbents for toluene absorption was investigated by means of
thermodynamic modeling and molecular dynamics (MD). The thermodynamic
models PC–SAFT and COSMO–RS were used to predict the vapor–liquid
equilibrium (VLE) of DES–toluene systems. PC–SAFT yielded quantitative
results even without using any binary fitting parameters. Among the DESs
consisting of three different HBAs and three different HBDs (phenol,
levulinic acid, ethylene glycol), [TEBAC][PhOH] was considered
as the most suitable absorbent. Systems with [TEBAC][PhOH] had
lowest equilibrium pressures of the considered DES–toluene mixtures,
the best thermodynamic characteristics (i.e., Henry’s law constant,
excess enthalpy, free energy of solvation of toluene), and the highest
self–diffusion coefficient of toluene. The molecular–level mechanism
was explored by MD simulations, indicating that [TEBAC][PhOH]
has the strongest interaction of HBA–/HBD–toluene compared to the
other DESs under study. This work provides guidance to rationally design
novel DESs for efficient aromatic VOCs absorption.