Extraction of heavy metal ions from leachate of cement-based stabilized waste using purpurin functionalized resin

A new chelating resin was synthesized by functionalization of a polymer support, Amberlite XAD-2 with purpurin through an azo linkage (-N=N-). The products were characterized by scanning electron microscopy, elemental analysis, Fourier transform infrared spectroscopy and thermogravimetric analysis. The optimum conditions for the extraction of Cd(II), Cr(III) and Pb(II) in two matrices; leachate from cement-based material and de-ionized water, were studied by batch and column methods. The determination of the metal ions was carried out by flame atomic absorption spectrometry. The optimum pH for the extraction of all metal ions in both matrices were at 4.0. Their sorption equilibrium was reached within 1 h. The sorbed Cd(II) and Pb(II) were eluted by 1% HNO3 within 10 min with the desorption recovery of >90%. The elution of Cr(III) by 3% H2O2 in 0.1 M NaOH was achieved within 30 min with the desorption recovery of >80%. The sorption capacity of Cd(II), Cr(III) and Pb(II) onto the resin was 75.0, 68.2, 82.7 μmol g-1 resin in DI water and 54.1, 46.5 and 55.7 μmol g-1 resin in leachate, respectively. The extraction efficiency in the column method can be improved using the recirculation system. This new method gave a good accuracy in batch system with the recovery of 86.5 and 89.9% for Cd(II) and Pb(II) and R.S.D. less than 2.3% (n = 14)