Journal of Membrane Science, Vol.130, No.1-2, 193-203, 1997
Kinetic Modeling of Cadmium Removal from Phosphoric-Acid by Nondispersive Solvent-Extraction
In this work it is reported that the kinetic modelling of the separation of cadmium from phosphoric acid by non-dispersive solvent extraction. Using Cyanex 302 as selective extractant, the extraction step was carried out in a hollow fibre module containing polypropylene fibres, whereas the concentration step required a ceramic module with tubular channels due to the high acidity of the backextraction agent. Application of the methodology previously reported by the authors led to the development of a kinetic model with three design parameters, i.e., equilibrium constant of the extraction reaction (ke’=6 x 10(3) mol(-2)/l(-2)), membrane mass transport coefficient of the extraction module (K-me=8.33 x 10(-8) m/s) and of the backextraction module (K-ms=3.33 x 10-8 m/s), that described satisfactorily the behaviour of the separation-concentration system. Thus, in this work a new application of the non-dispersive solvent extraction technology is presented, characterising at the same time the behaviour and parameters of a new type of contactor, i.e., a tubular ceramic module.