Solid phase extraction and preconcentration of Cu(II), Pb(II), and Ni(II) in environmental samples on chemically modified Amberlite XAD-4 with a proper Schiff base.

A new chelating resin, Amberlite XAD-4 loaded with N,N-bis(salicylidene)cyclohexanediamine (SCHD), was synthesized and characterized. The resin Amberlite XAD-4-SCHD was used for selective separation, preconcentration, and determination of Cu(II), Pb(II), and Ni(II) ions in water samples by flame atomic absorption spectrometry (FAAS). Effects of pH, concentration, and volume of elution solution; flow rate of elution; and sample solution, sample volume, and interfering ions for the recovery of the analytes were investigated. These metal ions can be desorbed with 0.5-M HNO3 (recovery, 98%-101%). The sorption capacity was found between 1.38×10(-1) and 3.58×10(-1) mmol/g. In order to evaluate the accuracy of the proposed procedure, the certified reference materials, BCR-032 (Moroccan phosphate rock) and BCR-715 (industrial effluent wastewater), were analyzed. The detection limits of the method were found to be 0.11, 1.91, and 0.43 μg/L for Cu(II), Pb(II), and Ni(II), respectively. The method was applied to the extraction and the recovery of copper, lead, and nickel in wastewater and other water samples.