Kinetic studies on organic acid extraction by a supported liquid membrane using functionalized polyorganosiloxanes as mobile and fixed-site carriers

A comprehensive model previously developed, which describes the kinetics and transport mechanism of a weak organic acid derivative through an integrated solvent-carrier supported liquid membrane (SLM), was used for the analysis of 1-lactic acid ethyl ester and phenol transport by the SLM system through the use of functionalized polyorganosiloxanes as mobile and fixed site carriers. The model was verified with the transport experimental data of 2 organic acids. The acid transport parameters, which include the product of solute partition coefficient and diffusion coefficient (KpDs), the equilibrium extraction constant (K-ex), and the sum of effective diffusivity of the solute-carrier complex due to both mobile and jumping carrier mechanisms (D-m + D-j), was determined. Excellent agreement is achieved between predicted and experimental data in most of the studies. Furthermore, the values of the effective diffusion coefficients (D-m + D-j), determined from experiments (curve-fitting), are in close agreement with the estimated values derived through the use of the Wilke-Chang and Lusis-Ratcliff correlations, and the values were also consistent in their orders of magnitude with the effective diffusion coefficients reported in the literature for various other substrates that were analyzed in similar systems.