Surface-activated anion exchange resins for synthesis and immobilization of gold and palladium nano- and microstructures

Abstract

A series of surface-activate anion exchange resins, bearing amino functionalities, were employed in processes of multiple adsorption and desorption of AuCl4−, PtCl62− and PdCl42− from solutions in 0.1 and 3mol∙L−1 HCl. The resins with ethylenediamine (EDA) and 1-(2-aminoethyl)piperazine (AEP) functionalities efficiently removed up to 100wt% of the noble metals, however, instead expected total elution, they revealed only up to 50wt% of desorption. The phenomenon was caused by the fact, that the anion exchange resins revealed an ability to reduce ionic forms of gold and palladium to their nano- and microparticles creating colloids and nanocomposites. For that reason the generated metallic forms were investigated using X-Ray Diffraction (XRD), Dynamic Light Scattering (DLS) and Scanning Electron Microscopy (SEM). The size of the obtained structures was in range of 50–1000nm, however, because reduction involves the transfer of an electron from a donor nitrogen it is dependent on the number of nitrogen atoms in amino ligands. A very close look at the changes in the resins' chemical structures has been taken using Fourier Transformation Infrared Spectroscopy allowing to determine a possible reason of the reduction.