Hydrothermal synthesis of nanocellulose-based fluorescent hydrogel for mercury ion detection

Cellulose nanofibers (CNF) possess excellent hydrophilicity, biocompatibility, high specific surface area and biodegradability, and the application of CNF to fluorescent hydrogels is one of the hotspots in the field of functional hydrogels. However, the rapid and efficient preparation of them remains a challenge, and it is necessary to explore its application in the detection of heavy metal ions. In this study, a hydrothermal method was adopted to investigate the one-pot synthesis of CNF-based fluorescent hydrogel (CFH) for mercury ion detection, which synchronously enabled CFH formation and in-situ carbon quantum dots synthesis. The as-prepared CFH had a complete 3D network structure, and epichlorohydrin showed positive effects on the mechanical properties of CFH. Moreover, excellent fluorescence performance can be achieved through regulating the synthesis process of carbon quantum dots. The as-prepared CFH showed different quenching effects in the Hg2+ solution with different concentrations, and the fluorescence intensity of CFH was closely related to the Hg2+ concentration in the range of 0–300 mmol/L, which showed great development potential and prospects in the fields of fluorescence probes on Hg2+ sensing and detection. This study provided a promising method for the rapid preparation of biocompatible and environment-friendly fluorescent hydrogel probes and ion detection materials.