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

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 3 mol ∙ L− 1 HCl. The resins with ethylenediamine (EDA) and 1-(2-aminoethyl)piperazine (AEP) functionalities efficiently removed up to 100 wt% of the noble metals, however, instead expected total elution, they revealed only up to 50 wt% 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 50-1000 nm, 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.