Highly magnetic TurboBeads were shown to adsorb Au ions at high efficiencies. This effect is based on the strong affinity between the carbon surface of the nanoparticles and the precious metal ions and is assisted by the reductive properties of the particles. Rossier et al. added Turbobeads to an aqueous gold solution. The gold ions were reduced to Au(0) in the proximity of the particles, deposited on the particle surface and could be removed magnetically. The system showed a high yield down to initial Au concentrations in the ppb level. In a second step the gold could be released from the particles by washing them in aqua regia displaying the possibility of recycling the magnetic TurboBeads.
Rossier et al. J. Mater. Chem. 2009 (link)
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