Supramolecular organogel with aggregation-induced emission for ultrasensitive detection and effective removal of Cu2+ and Hg2+ from aqueous solution

Herein, by rationally introducing multi-interactions sites, a new rhodamine derivative BT was successfully designed and constructed. The BT can further self-assemble into a stable supramolecular organogel BTG and exhibits strong pink-white aggregation-induced emission (AIE). Interestingly, the BTG exhibits selective and ultrasensitive sensing property for Cu2+. The limit of lowest detection (LOD) of BTG for Cu2+ is approximately 0.829 nM. By adding Cu2+ into the BTG, a no fluorescence Cu2+ coordinated metallogel BTG-Cu formed. Due to the competitive coordination of Hg2+, the BTG-Cu exhibits promising sensing properties for Hg2+, such as high selectivity and ultra-sensitivity, fluorescence turn-on response, instant response to Hg2+ (<2s), and the limit of lowest detection (LOD = 0.567 nM). In addition, the xerogel of BTG and BTG-Cu were able to remove Cu2+ and Hg2+ from diluted aqueous solution at an adsorption rate of 99.02% and 99.46%, respectively. The thin films based on BTG and BTG-Cu were prepared, which can act as not only a supramolecular fluorescent material but a simple and efficient tool for detecting Cu2+ and Hg2+, respectively.