KINETICS OF MN(II) TRANSPORT FROM AQUEOUS SULFATE-SOLUTION THROUGH A SUPPORTED LIQUID MEMBRANE CONTAINING DI(2-ETHYLHEXYL) PHOSPHORIC-ACID IN KEROSENE

Abstract

The permeation rate of Mn(II) from its aqueous sulfate solution through a solid supported liquid membrane containing di(2-ethylhexyl) phosphoric acid (D2EHPA) in kerosene as the mobile carrier has been studied as a function of hydrodynamic conditions, concentrations of Mn2+ (0.91-16.38 mol/m3) and H+ (pH 2.0-5.0) in the feed solution, carrier concentration (10-800 mol/m3) in the membrane, and temperature. It is observed that as the Mn(II) flux approaches a plateau region, the rate of permeation is predominantly controlled by diffusion through the membrane. On the other hand, at low Mn(II) and high H+ ion concentrations, the high diffusivity of the Mn-D2EHPA complex causes the overall permeation rate to be controlled by the interfacial reaction. It is also observed that the rate of Mn(II) permeation is first order with respect to dimer concentration up to 40 mol/m3 and half order above this concentration. Kinetic equations derived on the basis of the proposed mechanism are found to fit the experimental data satisfactorily.