Solution Thermodynamic
Properties of {Tetrabutyl Ammonium
Bromide:Glycerol} Hydrophilic DESs at T = 298.15–348.15
K and 0.1 MPa and an Approach over Solvent Extraction of Cr(VI) Using
{Tetrabutyl Ammonium Bromide:Decanoic Acid/Oleic Acid} Hydrophobic
DESs
posted on 2022-12-20, 14:07authored byK. Kadambanathan, R. Anantharaj
This study focuses on determining a pseudo-binary mixture’s
volumetric properties between 298.15 and 348.15 K temperature over
the whole mole fractions to understand the molecular interaction between
aqueous chromium solution and hydrophilic deep eutectic solvents (DESs).
The solution thermodynamic properties like the mixtures’ excess
molar volume, partial molar volume and excess partial molar volume
of individual components in the solution, apparent molar volume, partial
molar volume at infinite dilutions, and isobaric expansivity were
determined. Characteristics like the existence of functional groups,
thermal stability, phase transitions, and degree of acidity were investigated
using Fourier transform infrared spectroscopy, thermogravimetric analysis,
differential scanning calorimetry, and pH measurement of six prepared
DESs. For the extraction process, the hydrophilic glycerol in the
DES will be replaced by decanoic acid and oleic acid, which are hydrophobic.
The hydrophobic DES (HDES)-based extraction process was conducted
for three volume fractions under atmospheric conditions. HDESs were
used to remove heavy metal ions (25, 50, 75, and 100 ppm) from the
water stream. Notably, the extraction efficiency increased with the
concentration of chromium(VI) ions. Even at a lower concentration,
the extraction efficiency showed more than 94% for all HDESs. Before
and after extraction, chromium(VI) concentrations were analyzed using
inductively coupled plasma–optical emission spectroscopy.