Mass transfer rate in liquid anion exchange processes—II: Kinetic of iron(III) transfer in the biphasic system trilaurylamine hydrochloride-aromatic diluent, HCl-water

Abstract

The initial mass transfer rate of Fe(III) in the system trilaurylamine hydrochloride (TLAHCl)-aromatic diluent, HCl-water, has been studied in a constant interfacial area cell as function of the stirring speed of the phases, specific interfacial area and chemical composition of the system. The aromatic diluents benzene and toluene have been used. It has been shown that the rate of extraction is determined by interfacial chemical reactions occurring between the interfacially absorbed molecules of the liquid anion exchanger, TLAHCl, and the bulk species containing iron. Some evidence has been also obtained that the kinetically reactive aqueous iron species can be the neutral complex FeCl 3. A rate expression has been so derived and the rate constants of the interfacial reactions have been evaluated. The rate expression and rate constants have been found to be the same in both the organic diluents. By using the equilibrium law derived from the rate equation it has been demonstrated that distribution data can be predicted from kinetic measurements at time zero with a good degree of accuracy. Finally it has been proved that the proposed reaction mechanism does not vary with time and concentration vs time curves can be predicted from the calculated constants of the interfacial chemical reactions.