Dual functional rhodamine-immobilized silica toward sensing and extracting mercury ions in natural water samples

Abstract

A reversible solid optical sensor (SGIR) for Hg²⁺ based on silica gel was designed and synthesized. The binding and adsorption abilities of SGIR for metal cations were investigated with fluorophotometry and cold vapor atomic absorption spectrometry, respectively. The SGIR exhibits high selectivity for sensing Hg²⁺ over other metal cations in aqueous media because the Hg²⁺ ion selectively induces a ring opening of the rhodamine fluorophores, and the SGIR was also found to adsorb 72% of Hg²⁺ ion. The determination of Hg²⁺ in both tap and lake water samples displays satisfactory results, and the SGIR can also be easily recovered by treatment of a solution of TBA⁺OH⁻.