Rigidifying induced fluorescence enhancement in 2D porous covalent triazine framework nanosheets for the simultaneously luminous detection and adsorption removal of antibiotics

Considering the growing threat of antibiotics pollutant in water on human health and security, efficient detection and removal of antibiotics from wastewater remains an important but challenging task. In this work, by rigidifying the 4′,4‴,4″″′,4‴‴′-(ethene-1,1,2,2-tetrayl)tetrakis(([1,1′-biphenyl]-4-carbaldehyde)) (ETTC) monomer, an aggregation-induced emission molecule, in the framework, the obtained two fluorescent 2D ultrathin covalent triazine frameworks (F-CTFs) nanosheets display the high fluorescence quantum yield and high porosity. Therefore, the F-CTF nanosheets can detect nitrofurans (NFs) with highly selective and sensitive by fluorescence quenching. Particularly, the limit of detection (LOD) of nitrofurazone (NZF), nitrofurantoin (NFT) and furazolidone (FZD) are estimated to be 4.97, 8.08 and 13.35 ppb for F-CTF-1, and 1.75, 2.21 and 3.86 ppb for F-CTF-2, respectively, surpassing all the reported fluorescent materials. Meanwhile, the two F-CTFs also exhibit high adsorption capacity, fast adsorption rate for NFs, and the remarkable removal efficiency of 99% after equilibrium. In addition, the maximum adsorption capacities of the F-CTF-1 for NZF, NFT and FZD are 298, 200 and 154 mg/g, and that of F-CTF-2 for NZF, NFT and FZD are 351, 240 and 196 mg/g, respectively. More interestingly, adsorption-induced preconcentration effect has further enhanced the fluorescence detection performance of F-CTFs. Therefore, the combination of the rigidifying-induced fluorescence enhancement and the adsorption-induced preconcentration effect make sure that F-CTF-1 and -2 are excellent bifunctional materials for the selective detection and removal of especial NFs from water. The results indicate that the F-CTFs can rapidly and effectively detect and remove NFs antibiotics and may become practical in water quality inspection, wastewater treatment and environmental remediation.