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The adsorption and recovery of dysprosium ions (Dy3+) from industrial wastewater are necessary but still challenging. Herein, we constructed a series of defect-containing metal–organic frameworks (MOFs) [UiO-66-(COOH)2] using sodium benzoate (BCNa) as a modulator. Upon the formation of defects, the porosity and surface charge properties of the MOFs were improved, leading to a higher utilization ratio of active groups and higher adsorption capacities for Dy3+. The synthesized UiO-66-(COOH)2-B10 with an optimal addition of BCNa exhibited a superior adsorption capacity of 150.6 mg g–1. Fast adsorption occurred at ∼5 min, and equilibrium was reached at ∼60 min. Higher pH and temperature were found to be beneficial for boosting Dy3+ adsorption, and selective adsorption over other metal ions was achieved in a multicomponent solution. Further, FTIR spectroscopy and XPS investigations indicate that free carboxyl contributes to the capture of Dy3+. Thus, this work provides a promising strategy to enhance the utilization ratio of active groups and further adsorption performance.

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Metal-organic frameworks | Fluorescent probes | Phosphate | Monodentate ligand | AIEgen Herein, a novel sensor (TPE-UiO-66) was designed via anchoring monodentate tetraphenylethylene (TPE) onto UiO-66 framework. The combination of the distinct aggregation-induced emission (AIE) of TPE and the easy replacement of monodentate linker by guest phosphate, makes TPE-UiO-66 an ideal platform for sensing HPO 4 2-. Experimental results indicate that TPE-UiO-66 can selectively sense HPO 4 2from other common anions. The limit of detection (LOD) can reach to 5.56 μmol•L-1 and more importantly, TPE-UiO-66 also exhibits an ultra-fast equilibrium response of 2 min, far faster than those of other sensors especially for UiO-66-NH 2. The combination of experimental analysis and density functional theory (DFT) calculations demonstrates that the high selectivity, high sensitivity and fast response of HPO 4 2detection by TPE-UiO-66 can be attributed to the stronger coordination interactions of HPO 4 2with Zr-O cluster of UiO-66 than that of TPE molecule. This study not only provides a potential probe for phosphate, but also represents a novel strategy to design stimuli-responsive fluorescent MOF-based sensors via using monodentate AIEgens.