Solvent extraction of cadmium (II) from sulphate solutions using TOPS 99, PC 88A, Cyanex 272 and their mixtures

Extraction of cadmium (II) from sulphate solutions using organophosphorous-based extractants—TOPS 99, PC 88A and Cyanex 272 has been studied. Percent extraction of cadmium (II) increased with increasing equilibrium pH of the aqueous phase and extractant concentration. Extraction of Cd (II) by organophosporus extractants involves cation exchange mechanism with the formation of 1:3 metal to reagent complex. Characterization of the solid complex of cadmium with TOPS 99 by FTIR, 31P NMR supported metal complex formation with the phosphorus-hydroxyl (P-OH) group. Finally, the extraction behavior and possible separation of cadmium and nickel from the mixture of metals was studied.