Lactic acid that is prepared by fermentation is a compound in food, cosmetic pharmaceutical, and chemical industries. Since a simple technique is desired that separates lactic acid from the cultures, we propose lactic acid permeation through a poly(vinyl chloride)(PVC)-based membrane that contains deep eutectic solvents (DESs) as a carrier. Lactic acid was successfully permeated through polymer inclusion membranes (PIMs) containing hydrophilic DESs, urea-choline chloride and glucose-choline chloride. The permeation behavior was explained by the facilitated transport mechanism based on the solution-diffusion model. Simple preparation of thinner membranes in the PIM process and higher permeation rates are advantages over the supported liquid membrane process. The PVC-based membrane process containing environmentally benign hydrophilic DESs is promising for lactic acid separation on an industrial scale.
Keywords: deep eutectic solvent; lactic acid; polymer inclusion membrane.