Novel environmental applications of green tea: sensing and remediation of Ag+ in aqueous system

Abstract

The strong fluorescence of green tea was quenched with Fe³⁺ because of ligand-to-metal charge transfer and subsequent formation of magnetite (Fe₃O₄) nanoparticles (heavy metal effect). Ag⁺ restored the lost fluorescence by confining iron particles (capped with Cl⁻) with the formation of AgCl. Thus, toxic Ag was sensed in the aqueous system with a linear detection range of 10⁻⁴ M to 10⁻⁷ M and a detection limit of 4.1 × 10⁻⁹ M. The sensing protocol was applied for natural samples to detect Ag⁺. Gallic acid was found to be the pivotal component in the tea extract used to design a sensing platform. The company of the green tea were also varied and obtained comparable results.