CARRIER-MEDIATED TRANSPORT THROUGH SUPPORTED LIQUID MEMBRANES - DETERMINATION OF TRANSPORT PARAMETERS FROM A SINGLE TRANSPORT EXPERIMENT

This paper describes a time-dependent transport model for carrier assi sted cation transport through supported liquid membranes, The model de scribes the flux of salt as a function of time and two parameters viz. the diffusion coefficient of the cation complex (D), and the extracti on constant (K-ex). Simulations of transport experiments indicate that high extraction constants (K-ex) are responsible for the decrease in the transport rate in time. A simulation program (CURSIM) was designed that is capable of determining,the essential transport parameters D a nd K-ex from only one time-dependent transport experiment, The non-lin ear curve-fitting 'Down-hill Simplex' technique, gives directly the be st-fit values of D and K-ex. The CURSIM method was tested by evaluatio n of the transport of KClO4 by different calix[4] arene-crown-5 carrie rs and by valinomycin. Comparison of the results with those obtained p reviously by the initial flux approach, which requires a series of dif ferent experiments, shows a good agreement of both methods.