The enrichment and detection of mercury ions in fluorescent hydrogels

Mercury ions are easily converted into methylmercury, which is easy to accumulate in the body under the action of microorganisms and eventually cause damage to the human body. Therefore, the development of heterogeneous sensors for the enrichment and detection of mercury ion in wastewater is urgently required. In this paper, a fluorescent hydrogel integrating enrichment and detection is prepared by self-assembly combining hydrothermally synthesized nitrogen-sulfur-carbon dots with a hydrogel. The fluorescent hydrogel (AAH) is well characterized by scanning electron microscopy (SEM), Fourier Transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM), etc. The effects of solution pH, temperature, reaction time, and the Hg²⁺ enrichment ability in binary component system were investigated with static batch experiments on AAH. The porous structure and abundant chemical groups of AAH show excellent enrichment ability for mercury ions with the maximum adsorption capacity of 606.06 mg/g. In addition, the detection of Hg²⁺ by AAH is estimated by fluorescence analyses, which proves the sensitive fluorescence response and high selectivity to mercury ions. The results imply that AAH has great potential in environmental applications of mercury ion enrichment and monitoring.