Study of the Oxalate Ion Exchange Equilibria in Ion Exchange Resin Amberlite IRA-400

Abstract

The equilibrium constant in the standard state K_std for the uni-bivalent ion exchange between the resin (R) and the aqueous solution (aq)

                                        

where X^- = Cl^- or Br^- have been determined in anion exchange resin Amberlite IRA-400 with regards to mean activity co-efficients of ions both in the solution and in the resin. The apparent equilibrium constant (k_app) for various equilibrium concentrations of C₂O^2–₄ in the solution have been calculated from the expression.

                                   

The equilibrium constant in the standard state (k_std) is determined by a graphical method. The resin in its purely univalent anion form is chosen as the standard state. From k_std for vairous temperatures, the enthalpy change for the ion exchange reaction has been evaluated.