Thermodynamic Parameters from Ion Exchange Kinetics

DETERMINATION OF THERMODYNAMIC PARAMETERS FROM ION EXCHANGE KINETICS 

The connection between chemical equilibria and completely reversible reactions has been known for a long time (e.g., see Glasstone et al., 1941 Laidler, 1965). Keay and Wild (1961) determined enthalpy and entropy 

The general cation exchange reaction in a binary exchange system can be expressed as (Sposito, 1986)  

The rate of this reaction can be given as (Denbigh, 198T, Sposito, 

The individual rates vq and v i are affected by temperature, pressure, and the concentrations of the species in Eq. (5.36). At equilibrium, the left side of Eq. (5.37) will disappear and v]eq/v ]eq where eq is the equilibrium condition will be a function of temperature, pressure, and the equilibrium composition of the exchanger and aqueous solution phase. Because the activities of the species in Eq. (5.36) have an identical dependence, vleq/v leq depends on temperature, pressure, and the species activities (Denbigh, 1981). But this same relationship applies to the quotient of the right and left sides of Eq. (5.38) for the determination of the exchange equilibrium constant (Ksx) for the reaction in Eq. (5.36), which can be expressed as, 

---

Determination of Thermodynamic Parameters from Ion Exchange Kinetics 123... 

---