Applications Of Fluorescent Metal-Organic Frameworks For The Detection Of Metal Ions And Nitro-Compounds

Metal-Organic Framework ?MOF? is a range of organic-inorganic hybrid nanoporous materials. This type of material has high surface area, high adsorption quality, high porosity, good thermal stability and the peculiarities of structural divercity. We designed and completed the detection to the nitro-aromatic compounds and a series of metal ions work with two kinds of Al-MOF materials.cycu-3 is a kind of new type metal-organic framework material which has a large pore size of 3 nm. As verified by nitrogen sorption measurements, the cycu-3 exhibits the largest pore volumes and open channels of Al-MOFs as reported to date and shows good fluorescence ability.1. In this work, we synthesized the cycu-3 sample with the method of solvothermal. In order to investigate the crystal type and structure characteristics of cycu-3, we analyzed the XRD, FT-IR, SEM, BET and UV-vis of cycu-3. The results showed good crystal type and fluorescence properties. At the same time, the PL spectrums were detected which proved good fluorescent property of cycu-3.2. We choosed 8 nitro-aromatic compounds ?TNP, NB, DNB,4-NP, 3-NT,2-NP,2,6-DNT,2,4-DNT? under DMF solution for flourescence detection, concluding that the cycu-3 had a specific recognition effect for the selection of TNP, analyzed with the XRD and FL. patterns.3. We designed a series of reaction times to find the optimal testing time of cycu-3 to TNR Then the five regenerate detections of cycu-3 to TNP of 5×10-4 mol·L-1 were used to prove that the material had stables structure. At last, we did the UV absorption spectrum detections of the nitro-compounds, which showed the absorption spectra of TNP had the most obvious and largest overlap with the emission spectrum of cycu-3. The results showed that energy transfer mechanism was present in fluorescence quenching by TNP. Therefore, cycu-3 has higher selectivity and is more sensitive to TNP.4. We synthesized another Al-MOF, CAU-1-?OH?₂ with the method of solvothermal. The XRD, FT-IR, SEM, FL and UV-vis detections were performed to investigate the crystal type and structure characteristics of CAU-1-?OH?₂, which showed the good crystal type and fluorescence properties of the as-synthesized CAU-1-?OH?₂. The XRD pattern of water-immersed material showed consistent peak positions with the as-synthesized sample, which prved high water stability of CAU-1-?OH?₂.5. The detection to a series of aqueous solution of metal ions showed that the CAU-1-?OH?₂ samples had specific identification to Fe³⁺. Therefore, the material was almost entirely quenching when detecting Fe³⁺, besides, the color of the Fe³⁺-CAU-1-?OH?₂ system changed from light yellow to purple. Comprehensive analysized with the XRD and FT-IR adsorption spectra, the oxidation of Fe³⁺damaged the structure of CAU-1-?OH?₂, which resulted in the fluorescence quenching, achieving the purpose of detection.