Liquid membrane transport of Hg(II) by an azocalix[4]arene derivative

Abstract

A kinetic study of Hg(II) transport from an aqueous donor solution into an aqueous acceptor solution through a liquid membrane containing 25,26,27-triben-zoyloxy-28-hydroxy-5,11,17,23-tetra-(4-n-butylphenylazo)calix[4] arene I as a carrier was studied. The kinetic parameters (k1, k 2, Rm max, tmax, Jd max, Ja max) for the transport were investigated in terms of the effect of temperature, the stirring rate, the carrier concentration, and the type of solvent. The kinetics of transport was analyzed in the formalism of two consecutive irreversible first-order reactions. The membrane entrance rate, and exit rate constants were increased with increasing of temperature stirring rate, and carrier concentration. The membrane entrance rate and exit rate constants depended on the type of solvent and was found to be in order of CH2Cl2> CHCl3> CCl 4. The activation energy values are calculated as 30.67 ± 2.64 and 57.33 ± 4.90 kj mol-1 for extraction and reextraction, respectively. The values of calculated activation energy indicate that the process is diffusionally controlled by species.