Metal solutions of (Cu, Ni, Fe) were prepared by dissolving
copper sulfate (CuSO4Æ5H2O), nickel nitrate (NiNO3)2Æ6H2O
and iron sulfate (FeSO4Æ7H2O) separately in double distilled
water in order to result in known concentrations of the metal
ions required and to make synthetic wastewater