Pertraction of l-lysine by supported liquid membrane using D2EHPA/M2EHPA

• The application of supported liquid membrane for bio-separation was investigated.
• An experimental separation study of l-lysine monohydrate using supported liquid membrane was proposed.
• The mechanism for pertraction of l-lysine monohydrate from feed phase to strip phase was discussed.
• The parameters affecting pertraction of l-lysine monohydrate were analyzed.
• The main advantages of supported liquid membrane over the traditional separation methods were highlighted.

In this paper, an experimental study regarding pertraction of l-lysine monohydrate (l-lys) was investigated in an aqueous medium through a flat sheet supported liquid membrane (SLM) using a mixture of mono-(2-etylhexyl) ester of phosphoric acid (M2EHPA) and bis-(2-etylhexyl) ester of phosphoric acid (D2EHPA) as carriers and kerosene as diluent. Microporous hydrophobic PTFE membrane was used as support for the liquid membrane, and the strip phase was hydrochloric acid. The parameters affecting pertraction of l-lys, such as feed concentration, carrier concentration, initial feed pH, and stripper concentration were analyzed. It was found that these parameters strongly influence pertraction efficiency. Optimal experimental conditions for l-lys pertraction (pertraction efficiency of 33.4%) were obtained after a 4 h separation with l-lys feed concentration of 150 ppm, carrier concentration in the membrane phase of 35 vol.%, initial feed phase pH of 3, and hydrochloric acid concentration in the strip phase of 1 M. Stability of the SLM system was also studied. According to the stability experiments, it was observed that reduction of pertraction efficiency after 8 h is less than 6.8%.