Deposition of silver and gold nanoparticles on surface engineered silica particles and their potential applications.

This study focuses the attachment of gold and silver nanoparticles on commercial micron sized silica particles. The silica was functionalized with amine groups by a commercial silane surfactant and a layer-by-layer process employing polyelectrolytes, respectively. The nanoparticles were produced by conventional water based processes and the nanoparticles were functionalised by poly acrylic acid. The chemical analysis and X-ray photoelectron spectrometry clearly shows that the gold and silver nanoparticles can be attached to the functionalized silica by the used approaches. However, silane functionalized silica appears to result in a much more efficient uptake of the nanoparticles compared to layer-by-layer functionalized silica. 99% of gold and silver nanoparticle could be recovered and attached to the surface of the silane functionalized silica resulting in a concentration of 0.89 micromolAg/gSES (0.096 mgAg/gSES) and 1.53 micromolAu/gSES (0.301 mgAu/gSES) on the surface of the silica particles. The silver and gold coated silica particles were used for removal of Escherichia coli bacteria and radio frequency (RF) heating, respectively. The test indicate that the bactericide properties of silver and the RF heating effect of gold nanoparticles can be retained by attaching the nanoparticles to silica.