Functionalization of polyacrylonitrile/Na-Y-zeolite composite with amidoxime groups for the sorption of Cu(II), Cd(II) and Pb(II) metal ions

A composite material (PAN-Na-Y-zeolite) was prepared by polymerization of acrylonitrile in the presence of Na-Y zeolite. The composite was functionalized by amidoximation through the reaction of hydroxylamine on nitrile groups of the composite. The sorbent (APNa-Y-zeolite) was fully characterized by FTIR spectrometry, XRD diffraction, thermogravimetric analysis, scanning electron microscopy, zetametry and BET analysis. The sorption properties of APNa-Y-zeolite were investigated for the recovery of Cu(II), Cd(II) and Pb(II) from synthetic solutions before being tested for the purification of local tap water. Sorption properties were characterized through the study of pH effect, uptake kinetics, sorption isotherms. The pseudo-second order rate equation fitted well kinetic profiles. Sorption isotherms were modeled using the Langmuir, the Freundlich and the Sips equations. Thermodynamic parameters were evaluated through variation of temperature. While the sorption of Cu(II) and Cd(II) was endothermic, Pb(II) recovery was exothermic. Metal ions were successfully desorbed using 5 M HCl solutions. High concentrations of NaCl hardly alter sorption performance, contrary to humic acid that slightly reduces metal binding.