Silver nanomaterials sensing of mercury ions in aqueous medium

Heavy metal ions pollution has become a critical issue around the world. In order to develop highly efficient and accurate nanosensor at low cost, the application of nanomaterials for inorganic toxic elements (e.g. Hg2+, Pb2+, Cd2+, Cr6+, As3+/As5+, Cu2+) remediation and sensing has attracted significant attentions in academia and industry. In this review article, the application of Ag nanomaterials (Ag NMs) for colorimetric and fluorescent sensing of Hg2+ ions in aqueous medium has been summarized. Two plausible mechanisms for Ag NMs sensing Hg2+ ions have been proposed, namely, Hg2+ oxidization Ag(0) of Ag NMs to form Ag/Hg amalgam, and Hg2+ coordination with functional groups (e.g. -SH, -OH, -NH2, -COOH) of surface stabilizing organic molecules of Ag NMs. The resulted aggregation of Ag NMs, spectra shift of UV-vis absorption, as well as visual color changing have been utilized for the sensing of Hg2+ in aqueous medium. Various organic, inorganic and nanomaterial stabilizers, particularly natural products from plant extracts, have been systematically summarized for developing commercially available field-test Ag NMs-based nanosensor with high sensitivity and selectivity. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

Heavy metal ions pollution is a critical issue worldwide, and the use of nanomaterials for remediation and sensing shows great potential. This review article focuses on the application of Ag nanomaterials for colorimetric and fluorescent sensing of Hg2+ ions in aqueous medium, discussing the mechanisms involved and the development of commercially available nanosensors with high sensitivity and selectivity.