CATION-EXCHANGE PROPERTIES OF IRON(III) PHOSPHATE

Potentiometric titrations of iron(III) phosphate have been carried out in aqueous electrolyte solutions of KCl over the temperature range 29 9-333 K The data were explained by the law of mass action. Sorption of Cu2+, Zn2+, Co2+ and Ni2+ on iron(III) phosphate was studied over the temperature range 298-323 K. The sorption data fitted the linear form of the Langmuir adsorption equation, Further, the extent of sorption was found to increase with increase in temperature and concentration. The order of selectivity was found to be CU2+ > Zn2+ > CO2+ > Ni2+. Th e values of the Langmuir constants were used to calculate the thermody namic parameters: DELTAG0, DELTAH0 and DELTAS0.