Sorption of divalent metal ions on CrPO4

The divalent metal ion sorption (Cu2+, Cd2+, Ni2+, and Pb2+) on chromium phosphate (CrPO4) was studied as a function of pH, temperature, and concentration of metal ions. The sorption of metal ions is observed to increase with the increase in pH, temperature, and concentration of metal ions in solution. The mechanism of sorption is found to be the exchange of the hydrolyzed metal cations with the protons from solid at high temperature. The sorption at low temperature is found to be accompanied by the precipitation of the corresponding metal phosphates such as Pb3(PO4)2.