Kinetic analysis of chromium(VI) ions transport through a bulk liquid membrane containing p-tert-butylcalix[4]arene dioxaoctylamide derivative

A kinetic study of chromate ions (Cr(2)O(7)(2-)) transport from an aqueous donor phase into an aqueous acceptor phase through a bulk liquid membrane containing p-tert-butylcalix[4]arene dioxaoctylamide derivative as a carrier was studied. The influence of pH on donor and acceptor phase, effect of chromate and carrier concentration, type of solvent, stirring speed and temperature were investigated. The kinetic parameters (k(1), k(2), R(m)(max), t(max), J(d)(max), J(a)(max)) were calculated for the interface reactions assuming two consecutive, irreversible first-order reactions. The activation energy values are calculated as 16.89 and 10.34 kJ mol(-1) for extraction and reextraction, respectively. The values of calculated activation energy indicate that the process is diffusionally controlled by chromate ions. The experiments demonstrated that p-tert-butylcalix [4]arene dioxaoctylamide derivative is a good carrier for Cr(VI) transport through liquid membranes in this study. (C) 2007 Published by Elsevier B.V.