Synthesis Of Novel Fluorescent Chemosensors And Their Recognition Properties

Most of the nitroaromatics are explosive materials, the improper handling of them will be a serious threat to human life and property security, the leaking of them into the environment will be harmful to the ecological environment. Mercury ions are one of the most toxic heavy metal elements and can cause serious harm to the environment and the human health. Therefore, the detection of the above pollutants existing in the organism and the environment has attracted great attention. The traditional instrument methods of detecting these pollutants, such as spectroscopy and mass spectrometry, are complicated, time-consuming and expensive, and it is difficult to meet the requirement of on-site rapid detection. Researchers are committed to developing a high sensitivity, selectivity, required less sample and simple method, which is used to detect the above pollutants. At present, the fluorescent sensor materials have attracted much attention due to their excellent performance in pollutant detection.In this paper, we prepared two fluorescent chemosensors based on organic and inorganic fluorescent materials for detection and identification of nitroaromatics or Hg+The rare earth metal organic framework Tb-BTC (MOF-76) was synthesized by hydrothermal method, then the Au/Tb-BTC was obtained by dispersing the gold nanoparticles (Au NPs) on the surface of the Tb-BTC. A bifunctional fluorescent chemosensor R/Au/Tb-BTC for detecting trinitrotoluene (TNT) and Hg2+ was prepared by functionalizing Au/Tb-BTC with rhodamine B derivatives (R). The results showed that the introduction of the Au NPs changed the crystal form of Tb-BTC, but did not affect its luminescent properties. The fluorescent chemosensor R/Au/Tb-BTC not only can detect TNT in ethanol solution, but also can detect Hg2+ in aqueous solution, and owns excellent selectivity and competition ability. Moreover, when TNT and Hg2+ coexist in ethanol solution, the R/Au/Tb-BTC could detect them respectively using different excitation wavelengths. In addition, the chemosensor was regenerated by simple chemical treatment, and can resue to recognize TNT and Hg2+ for several times.The mesoporous molecular sieve Tb-HMS, which doped with rare earth metal Tb, was prepared by hydrothermal method. Then the Au NPs were dispersed on the surface of mesoporous materials and the Au/Tb-HMS was obtained. A fluorescent chemosensor MPA/Au/Tb-HMS was prepared by functionalizing Au/Tb-HMS with 3-mercaptopropionic acid (MPA). The results showed that the Au NPs did not destroy the internal pore structure of Tb-HMS, but the MPA damaged the inner channel structure of mesoporous molecular sieve in some degree. The chemosensor had a certain ability to detect Hg2+, but the interferences of Ag+ and Cu2+ was larger.