Study On The Construction And Performance Of The Modified Dicarboxylic Acid Zr-MOF After Synthesis

In this paper,three kinds of main frameworks?MIL-140C,UiO66-NH₂,UiO66-?OH?₂?with zirconium?Zr?as the metal node were synthesized.The similar size and pore size,and the same coordination mode are shown,which are electrically neutral,positive,and negative respectively.Fluorescent materials with fluorescence sensing potential(Eu³⁺/TFA@MIL-140C,Eu³⁺/TFA@UiO66-?OH?₂,Eu³⁺/TFA@UiO66-NH₂)were prepared by post-synthesis modification method,confirmed by X-ray diffraction.The three composite materials maintain the same three-dimensional structure as their MOF precursors?MIL-140C,UiO66-?OH?₂,UiO66-NH₂?.The isotherm adsorption curve of nitrogen adsorption confirmed that the pores of the MOF were occupied during the modification synthesis,and the pore size distribution was calculated from the adsorption curve confirmed that the construction of the second fluorescence center?Eu/TFA?was carried out inside the tunnel of MOF.Moreover,the heavy metal effect of Cu²⁺ions is used to adjust the characteristic peak emission intensity of Eu³⁺ions,and a composite material with capability to detect H₂S was constructed.Fluorescence tests showed a significant decrease in the intensity of the characteristic emission peak of Eu³⁺ions with the interaction of Cu²⁺ions.The water phase detection of hydrogen sulfide?H₂S?was tested and confirmed that the three complexes have fluorescence recovery response to H₂S?with NaHS as donor?in the visible region,and exhibit excellent selectivity,stability and repeatability,which allows for specific recognition of H₂S.Among the three composite materials constructed in this paper,the composite with negative electron framework UiO-66-?OH?₂ is the best,and its limit of detection?LOD?is 5.83?M,And the LOD of the composite materials with the cationic framework and the uncharged framework as the host were 11.7?M and7.43?M,respectively.