Calorimetric determination of proton/sodium(1+) ion exchange on .alpha.-titanium phosphate

Cation-Exchange Properties of Aluminium(III) Phosphate

Potentiometric titrations of aluminium(III) phosphate have been performed in the presence of aqueous electrolyte solutions containing Cu2+, Zn2+, Ni2+ and K+ ions as a function of the concentration of the latter, the pH and the temperature. The sorption of Zn2+ ions has also been studied and the data for metal ion sorption shown to correlate with the Potentiometric titration data, indicating that the process responsible for metal ion uptake is ion exchange. The pKa value of the exchanger and its thermodynamic parameters have been evaluated.

The mechanisms of Ni2+ ions sorption by AlPO4

Sorption of Ni2+ ions by AlPO4 is studied as a function of concentrations and temperature at pH 7. Potentiometric titration, dissolution and FTIR studies are employed to determine the mechanism of the process of the uptake of Ni2+ ions which is found to be both the ion exchange and the surface precipitation of the corresponding metal phosphates. Freundlich equation is found applicable to the sorption data, and is employed to evaluate the thermodynamic parameters deltaH(o) and deltatS(o).