Chemosensory rhodamine-immobilized mesoporous silica material for extracting mercury ion in water with improved sensitivity

Mesoporous silica material, SBA-15, is an excellent support for constructing fluorescent surface sensor. In this paper, we reported a three-step surface reaction involved strategy to construct efficient fluorescent surface sensor for mercury ion by clicking rhodamine fluoroionophores onto APES-functionalized SBA-15, which is fully characterized by IR spectra, TGA analysis, elemental analysis, nitrogen adsorption experiment and TEM. Our experimental results indicated that such a strategy exhibits an obviously higher loading efficiency within SBA-15 than a previously reported strategy. The Hg²⁺ extracting efficiency for SBAIR was found to be enhanced (ca. 89%). In addition to the high selectivity, the current chemosensor shows improved sensitivity and can respond to Hg²⁺ as low as ppb level (1.0 × 10⁻⁸ M, 2 ppb) in water.