Size characterization of silver nanoparticles after separation from silver ions in environmental water using magnetic reduced graphene oxide.

This study involved the synthesis of magnetic reduced graphene oxide (M-rGO) using a co-precipitation method and examined its resultant adsorption properties for mixtures containing silver ions and silver nanoparticles (AgNPs). The results indicate that M-rGO preferentially adsorbs silver ions in mixtures containing AgNPs, enabling the size characterization of smaller AgNPs (<60nm) at ultra-trace concentration levels to be more attainable. The sorbents after adsorption could be easily recovered through an external magnet. The AgNPs retained in solution were characterized using single-particle ICPMS (SP-ICPMS). The adsorption behavior of silver ions on M-rGO was well fitted with the pseudo-second-order kinetic model and the Freundlich adsorption isotherm model, with the conclusion that the adsorption of silver ions occurred primarily through the chemical bond effect and the heterogeneous surface of the sorbent. Finally, the application of M-rGO with the approach developed herein to actual environmental water samples was successful.