Thermodynamics of ion exchange between clinoptilolite and aqueous solutions of and

Silver, zinc, and copper exchange in a Na-clinoptilolite and resulting effect on antibacterial activity

“…Since homoionic Na-clinoptilolite was prepared at 60 jC whereas the equilibrium studies were conducted at 25 jC, it seems reasonable to assume that potassium, calcium, and magnesium present in Na-clinoptilolite are in inaccessible ion exchange sites and do not participate in the ion exchange process at 25 jC. For this reason, CEC was calculated as 1.87 meq/g corresponding to total equivalents of sodium in the Gördes clinoptilolite as proposed by Pabalan (1994).…”

Ion exchange equilibria in zeolite minerals

“…A commonly used activity coefficient expression for dilute electrolytes is given by Glueckauf (1949), although other expressions exist for more concentrated solutions. A comprehensive description of the procedure for obtaining the thermodynamic quantities connected with cation exchange reactions involving zeolites may be found in several papers (Townsend 1986;Grant and Fletcher 1993;Pabalan 1994: Caputo et al 1995.…”

Volume II: near-field and altered-zone environment report

“…3.4.3 .4.2.3 Eflect~cation-exchange.The thermodynamic data for Na-clinoptilolite (Barnes~d Wm, 1995) provide a basis for the c~c~ation of the end-member thermodynamic properties of K-and Ca-and Sr-clinoptilolite by incorporating the results of Pabalan (1994) and Pabalan and Bertetti (1994). The latter studies are binary cation-exchange experiments for Na-K, Na-Ca, and Na-Sr compositional pairs.…”

“…As discussed by Pabalan (1994), cation-exchange in clinoptilolite is accompanied by hydration and dehydration reactions. Consequently, the Gibbs free energy of exchange measured by Pabalan contains a contribution due to hydration reactions in 3-42 addition to cation-exchange.…”