Silica-based Materials for Mercury Detection and Removal: A Chelation-Free Solution.

Abstract

In this study, we introduce a chelation-free approach to the dual-functional detection and removal of Hg2+ ions using two novel silica-based materials, AnSiO2 and PySiO2, functionalized with anthracene and pyrene, respectively. These materials were synthesized via a two-step process involving the direct condensation of triethoxyvinylsilane onto silica gel surfaces, followed by Heck coupling with 9-bromoanthracene and 1-bromopyrene, respectively. They exhibit strong fluorescence emission in aqueous solutions, particularly at pH 6. Upon exposure to Hg2+ ions, both materials undergo significant fluorescence quenching, enabling sensitive and selective detection of Hg2+. PySiO2 demonstrated superior performance compared to AnSiO2, with a lower detection limit (0.29 µM) and a higher Stern-Volmer constant (2 × 106 M-1). Additionally, PySiO2 shows a higher adsorption capacity for Hg2+, reaching 54.04 mg/g, as confirmed by ICP-MS analysis. The sensing mechanism involves charge-dipole and π-electron interactions, supported by spectroscopic analyses. Reusable for four cycles, PySiO2 effectively removes Hg2+ from aquaculture water, showcasing its potential for scalable, cost-effective, and simultaneous detection and remediation of mercury in real-world applications.