Removal of Some Heavy Metal Ions Using Grafted Polyurethane Foam

Abstract

Polyurethane (PU) was modified by grafting a mixture of two monomers acrylonitrile/acrylic acid (AN/AAc) by gamma irradiation method. Effects of various parameters such as, concentration of comonomer composition, grafting yield, gamma irradiation doses, dose rates and pH of adsorbent on the adsorption capacity were studied. Characterizations of the grafted polyurethane (PU-g-AN/AAc) were investigated using infrared (IR) spectroscopic analysis, X-ray diffraction (XRD) and scanning electron microscope (SEM). Moreover, the adsorption capacities of some heavy metals such as, Zn(II), Fe(II), Ca(II), Ni(II), Cu(II) and Pb(II) onto PU-foam and PU-g-AN/AAc were studied. The efficiency of such grafted polyurethane foams for uptaking different previous metal ions was determined and compared with that of natural granular activated carbon (GAC). The uptaking of metal ions was remarkably affected by the pH of the solution, the valances of metal ions, atomic weight and its initial concentrations. Equilibrium isotherms and interruptible diffusivities were investigated through batch experiments in analyzing the uptaking of aqueous solutions of metal ions onto PU foam, grafted PU, and granular activated carbon. The Frundlich constants k and 1/n have been determined for each metal ion to represent both the ability and the affinity of that ions towards the uptaking materials, respectively.