Cleaved disulfide cross-linking functionalized silica nanoparticles for enrichment of Cd (II)

We successfully introduced a cleaved disulfide on the surface of silica nanoparticles (SNPs), which can be used to enrich Cd (II) ion in aqueous solution. Firstly, the thiol-coated SNPs reacted with 4,4′-dithiodipyridine to form disulfide linkage on the surface of nanoparticles, then benzimidazole molecules were grafted on the surface via a cleaved disulfide linkage. TEM, FT-IR and XPS were used to characterize the process of preparation. After Cd (II) was adsorbed and enriched, the disulfide linkage was cleaved by addition of reduced glutathione solution. The enrichment results showed that the concentration of Cd (II) increased around 10 times as much as initial solution, which suggesting that the cleaved SNPs have a good capacity of enrichment of Cd (II).

Benzimidazole molecule modified silica nanoparticles can be used to adsorb Cd (II) ion at room temperature. By adding the reduced glutathione solution, Cd (II) ion can be released from the silica, which can enrich the trace Cd (II) ion from the dilute solution.Figure optionsDownload as PowerPoint slideHighlights
► Benzimidazole molecule has been grafted onto the silica nanoparticles via the disulfide bond.
► Disulfide bond can be cleaved by the attack of glutathione (GSH).
► The modified silica nanoparticles were used to enrich cadmium ion in the aqueous solution.
► The enrichment efficiency of Cd (II) ion could increase about 10 times as much as that of initial solution.