Recovery and separation of precious metals using waste paper

An adsorption gel was prepared from waste paper by immobilizing iminodiaectic acid so as to investigate its adsorption behavior for various metal ions from chloride media. The gel was found to be selective for Au-III and Pd-II over Pt-IV and other base metal ions including Cu-II, Fe-III, Ni-II and Zn-II at varying concentrations of hydrochloric acid. Moreover, Au-III was reduced by the gel giving rise to clearly recognizable beautiful elemental gold particles which was confirmed by means of the XRD-spectrum and SEM-images of the adsorbent after adsorption. This result has increased the prospect for mutual separation of Aunt and Pd-II from coexisting Pt-IV and base metals.