Supported liquid membranes with feed dispersion for recovery of Cephalexin

• Pertraction through SLM with feed dispersion was proposed and demonstrated.
• The mass transfer mechanism of the SLM-FD technique was elucidated and modeled.
• Various operating parameters were investigated to identify the critical ones.
• Cephalexin concentration in the feed phase can be flexibly controlled by using SLM-FD.
• The advantages of SLM-FD over solvent extraction and SLM-SD were illustrated.

Pertraction through supported liquid membranes with feed dispersion (SLM-FD) has been proposed and studied for simultaneous removal and recovery of Cephalexin from aqueous solutions using a commercially available hollow-fiber module and the carrier Aliquat 336. The feed dispersion, formed by dispersing the feed solution in the organic membrane solution with a mixer, flowed through the shell side of the module, forming the SLM in the nanoporous hollow fibers. Various parameters were investigated including the feed-to-organic volume ratio, initial Cephalexin concentration, Aliquat 336 concentration in the organic membrane solution, KCl concentration in the strip phase, shell side feed-dispersion flow rate, and lumen side strip-solution flow rate. The results showed that an excess of counter ion, KCl, was needed for facilitated transport and that the shell side and lumen side flow rates had little effects on mass transfer performance. The mass transfer process of SLM-FD was elucidated, and a mathematical model was developed to describe the process. Based on this model, both the theoretical and experimental overall mass transfer coefficients were obtained as a function of Aliquat 336 concentration. These mass transfer coefficients were in reasonably good agreement. The average overall mass transfer coefficient obtained was significantly larger than (about 1.7 times) that attained by using the supported liquid membrane with strip dispersion (SLM-SD). In addition, the SLM-FD was shown to be superior to the solvent extraction process in terms of Cephalexin removal from the feed solution.