Kadsura-Shaped Covalent–Organic Framework Nanostructures for the Sensitive Detection and Removal of 2,4,6-Trinitrophenol

The detection and removal of 2,4,6-trinitrophenol (TNP) are extremely important because of the growing levels of pollution in the environment and water sources. In this paper, a multifunctional material based on Kadsura-shaped fluorescent covalent–organic framework (COF) nanostructures was developed and applied to the simultaneous sensitive detection and effective removal of TNP for the first time. Kadsura-shaped fluorescent COFs with stable nanostructures were obtained by a facile one-step synthesis strategy at normal temperature. It should be noted that TNP could prominently and rapidly quench the fluorescence of Kadsura-shaped COFs by the inner filter effect (IFE), with a detection limit of 1.7 nM and a linear range of 5.0 × 10–3–2.0 × 102 μM. The established method could be successfully employed for the analysis of TNP in a natural water environment. Moreover, a filter-paper-sensing element for the visual detection of TNP was also fabricated, which provided an effective and efficient visualization platform for TNP detection. Meanwhile, as an adsorbent, Kadsura-shaped COFs could effectively adsorb and remove TNP in the samples. The maximum saturated adsorption capacity of Kadsura-shaped COFs was 656 mg/g, which was the maximum reported thus far. The proposed approach could not only achieve fluorescence detection and visual analysis of TNP but also remove TNP in environmental samples, which provided a modest contribution to environmental protection.