COMBINED MASS AND ENERGY-BALANCE ANALYSIS OF AN ELECTROCHEMICALLY MODULATED EQUILIBRIUM STAGE PROCESS

A cyclical electrochemical process for the removal of a solute from a feed phase and concentrating it in a receiving phase is studied. The extraction and release of the solute are based on the complexation reactions with the reduced and oxidized forms of the complexing agent in a third contacting phase. The magnitude of the two distribution coefficients play an important role in this equilibrium process. A combination of mass and energy balances are used to determine the amount of solute transferred from a feed phase to a receiving phase using a graphical method. The minimum theoretical voltage required for this process is derived and found to be dependent on the reaction equilibrium constants. The work involved in such a process is also a function of the reaction equilibrium constants, the ratio of carrier to solute concentration, and the number of stages required for a certain separation criteria. The thermodynamic efficiency can be large, compared to some other separation processes, with the appropriate combination of the key parameters.