The effects of stirring speed on coupled transport of nitrite ions through liquid membranes

Abstract

In this study, the appeals of stirring speed on coupled transport of nitrite ions through liquid membranes has been investigated at various stirring speeds in the range of 100-250 rpm. Coupled transport of nitrite ions through liquid membranes (cp = 85 % hexane + phi = 15 % trichlorometane) containing tetraoctyl ammonium chloride (TOACl) as a carrier, was examined. For the diffusion of the nitrite ion-carrier complex at various stirring speeds through the narrow boundary layers at the interface of the membrane, the variable membrane entrance (k(1d) and exit rates (k(2m) and k(2a)) are the rate determining steps. The activation energies of membrane entrance and exit permeate rates for nitrite ions are E-am = 1.58 and E-aa = 1.583 kJ mol(-1), respectively. From these experimental results, it was concluded that the reaction was diffusion controlled. The membrane was stable during the transport experiments (no leakage of carrier and carrier-nitrite ion complexes to both aqueous phases and also there was no supplementary water penetration into the membrane was observed). This favours the interfacial character of nitrite ion-carrier complexion reaction.