Abstract
This work focused on the potential of glycerol as a
scrubbing solvent for stripping of highly polar volatile organic
compounds (VOCs) from industrial waste gas streams. Results
for glycerol interactions were compared to those of water.
Solubility predictions in the form of infinite dilution activity
coefficients were made using the Modified UNIFAC Dortmund
group contribution model, which was set up on a Microsoft
Excel spreadsheet specifically designed for this purpose.
Activity coefficients for VOCs in water and glycerol (highly
polar solvents) increased with an increase in the length of the
VOC solute nonpolar tail. Furthermore, activity coefficients
decreased with an increase in the degree of branching of the
VOC solute. The results show that low chain length highly polar
alcohol, ketone, organic acid and aldehyde solutes are very
soluble in glycerol. Diols, dicarbonyl aldehydes, some ketone
derivatives and the ethanolamines also show good solubility.
Highly polar diesters and ester derivatives are less soluble in
glycerol and water. This study has found glycerol to be a better
scrubbing solvent than water in treating highly polar VOCs.
However it is possible that the standard method of building up
the glycerol molecule in the UNIFAC may result in
under-predictions of activity coefficients and thus special group
interaction parameters for glycerol are required.