Performance of different ionic liquids to remove phenol from aqueous solutions using supported liquid membrane

Abstract

An experimental study was carried out for the removal of phenol from aqueous solutions using supported liquid membranes containing ionic liquid (IL) as the carrier solvent. The commercial grade ILs namely: [CYPHOS^® 101], [CYPHOS^® 102], [CYPHOS^® 103], [CYPHOS^® 104], [Aliquat 336^®], and [C₈MIM][PF₆] were used as membrane phase in this work. The effect of various parameters such feed phase pH, operation time, and stirring speed on the removal of phenol has been investigated using the six different ILs. Supported ionic liquid membrane (SILM) through vacuum immobilization method was used for the removal of phenol. The maximum permeation rate of 75.63% was achieved over an experimental run of 24 h at pH 4. High permeation rate was obtained by [CYPHOS^® 104] among all the six ILs studied. The order of the permeation rates followed: [CYPHOS^® 104] > [CYPHOS^® 103] > [CYPHOS^® 102] > [CYPHOS^® 101] > [C₈MIM][PF₆] > [Aliquat 336^®]. The operational stability and performance of the supported liquid membranes were studied via characterization techniques such as scanning electron microscopy, energy dispersive X-ray, and FTIR analysis. The mechanism of phenol transport through SILM was also proposed.

Keywords:

• Ionic liquid
• Phenol removal
• Liquid membrane
• Wastewater treatment

Acknowledgments

The authors gratefully acknowledge that this work was financially supported by the research grant under the Fast Track Scheme from the Department of Science and Technology (DST), Government of India vide sanction No. SR/FTP/ETA-56/2010.