An innovative strategy for construction of pH-responsive supramolecular hydrogel from graphene quantum dots clusters toward integration of detection and removal of uranium

A novel supramolecular hydrogel (GQDs-GSH), generated from self-assembly between the reduced graphene oxide (RGO) and in-situ formed graphene quantum dots (GQDs), was fabricated by using one-step hydrothermal route. In the hydrogel, the GQDs clusters that produced by the aggregation of GQDs acted as the good cross -linkers, pillars and surface stabilizers to bind RGO building blocks via multiple hydrogen bonding to construct interconnected 3D porous network. Otherwise, the as-prepared hydrogel exhibited special pH-responsive on-off switchable fluorescence behavior, which means that the reversible process referred to stripping and reloading of GQDs in the hydrogel was regulated by the pH stimulation. Sequentially, GQDs-GSH was applied for U(VI) detection with a good linear relationship (R-2 = 0.999) and high selectivity, followed by effective U(VI) removal and feasible GQDs recovery from aqueous solution. These exciting findings reveal good promises of GQDs for the preparation of 3D architectures and provide a potential platform for integrated detection and treatment of pollutants.