Heterogeneous Chemical Equilibrium: Evaluation Of Equilibrium Constants Of Ion Exchange Processes Between Hydrogen Ions And Trivalent Chelated Metal Counter Ions In Some Coordination Biopolymers Of Metal- Alginate Complexes

Hassan RM

Published on: 2019-11-05

Abstract

Complexometric and titrimetric techniques have been applied for studying the heterogeneous chemical equilibrium for cation-exchange processes between some chelated such as Al3+, Cr3+, Fe3+, La3+ and Ce3+ counter ions in its respective coordination biopolymer metal-alginate complexes of granule nature and H+ ions of HClO4 acid electrolyte at a constant ionic strength of 0.1 mol dm-3. The factors that affected the ion exchange processes such as ionic radius, nature of metal ion, coordination geometry of chelation in the complex, the strength of chelation between the chelated metal ion, the functional groups within the macromolecular chains of alginate and the temperature have been examined. The thermodynamic parameters of ion exchange processes in such heterogeneous equilibria have been evaluated and discussed in terms of the coordination geometry and complexes stability. The values of equilibrium constants were found to increase in the order Al < Fe < Cr < Ce < La-alginate complexes which are indicative of decreasing the stability in the same order.