Jornal de Ciência e Tecnologia de Membranas

Abstrato

Heterogeneous Equilibria: An Equilibrium Study of Ion Exchange Process between Hydrogen Ions and Divalent Metals Counter Ions in Some Coordination Biopolymer Metal-Alginate Gel Complexes

Refat M Hassan, Samia M Ibrahim

Heterogeneous chemical equilibrium for ion exchange process between divalent metal counter ions in the coordination biopolymer metal-alginate complexes and the H⁺ ions of HClO₄ acid electrolyte at a constant ionic strength of 0.1 mol dm^-3 have been investigated using complexometric and titrimetric techniques. The factors affected the ion exchange processes such as the nature of the complexes geometrical configuration, the ionic radii of chelated metal ions, the bonding strength between the metal ions and the functional groups of alginate macromolecule and the temperature have been examined. The thermodynamic parameters of the ion exchange equilibrium have been evaluated and discussed in terms of the coordination geometry, strength of chelation and complexes stabilities. The experimental results indicated that values of the equilibrium constants of exchange were decreased in the order Mn>Co>Zn>Ca>Ni>Pb>Sr>Cd>Sn>Hg>Cu>Ba metal- alginate gel complexes, whereas the stability was increased in the same order.