DIMENSIONLESS OVERALL DRIVING-FORCE AND A POTENTIAL PLANE IN EXTRACTIVE MASS-TRANSPORT BETWEEN NITRIC-ACID AND 30-PERCENT TBP DILUTED IN N-DODECANE

The variations of solute concentrations in aqueous solutions and extra ctants of 30% TBP/n-dodecane were traced experimentally during forward and reverse transport of U(VI), Re(VIT) and HNO3. Besides, a theoreti cal attempt was made to describe the transient mass transport between two liquid solutions. The states of a solute during mass transport hav e been represented in an implicit form of time using new state functio ns A and A, which are defined by the bulk concentrations of a solute. and the derivatives of A with respect to a. The simultaneous transpo rt fluxes of solutes in the forward and reverse directions have been c onfirmed to be an almost linear function of the first derivative, exce pt for HNO3 accompanying simultaneous transport of a. macro amount of U(VI). The first derivative is regarded as a dimensionless overall dri ving force for mass transport irrespective of transport direction; sin ce the first derivative is expressed by the liquid volume and bulk con centrations of a transferring solute, and also as a function of conven tional linear driving force. Furthermore, the driving farce has been o btained as the gradient of a transport potential cur ie with respect t o A where the curve is on a plane in three-dimensional space.