Intensified liquid-liquid extraction of biomolecules using ionic liquids in small channels

The continuous extraction of an amino acid from an aqueous solution into an ionic liquid phase was studied experimentally in small channels, demonstrating a double intensification of the solvent used and the overall process. Channels with 0.5, 1 and 2 mm internal diameter were used for the extraction of the amino acid, Ltryptophan from an aqueous solution (0.005 mol L-1), into a hydrophobic ionic liquid, 1-Butyl-3-methylimidazolium Bis (trifluoromethanesulfonyl)imide, [C4mim][Tf2N] in the presence of a crown ether extractant , Dicyclohexano-18-crown-6, (DC18C6). A mechanism was proposed for the extraction which involved the ammonium centre of the amino acid forming hydrogen bonds with the 18-crown-6 part of the extractant at a 1:1 ratio. Partition coefficients up to 25 were obtained. The continuous extraction experiments were carried out during plug flow where the interfacial areas reported reached up to 5500 m2m- 3 at 50% volume fractions. Extraction efficiencies up to 90% were obtained for residence times less than 30 s. Overall mass transfer coefficients (KL alpha) found reached up to 0.14 s-1.

Automated summary

The experimental study on the continuous extraction of an amino acid from an aqueous solution into an ionic liquid phase demonstrated a double intensification of the solvent used and the overall process. Efficient extraction of the amino acid into the ionic liquid with high mass transfer coefficients was achieved in small channels, indicating promising potential for industrial applications.