Design And Synthesis Of 3D COFs Based On Thioether For Mercury(?) Removal

Covalent organic frameworks(COFs),in which organic building blocks are connected by covalent bonds,are a new class of crystalline porous materials.Compared with other traditional porous materials,COFs possess high surface area,low density,good stability and designable structure.And COFs have shown potential application in gas separation and storage,catalysis,sensing,optoelectronics and energy storage.Compared with the layer stacked 2D COFs,3D COFs contain higher surface area and numerous open sites,which make them ideal candidates for adsorption or catalysis.However,due to their synthetic challenges and complicated structure determination,3D COFs have been underdeveloped for many years,especially the research of functionalized 3D COFs are far away behind.In this thesis,based on the unique physical and chemical properties of thioether compounds,we designed and synthesized a thioether based 3D COF(3D-TPB-S-COF)and explored its application in mercury ion adsorption.The main contents of the thesis are list as follow:1.Firstly,we designed and synthesized a new quadrilateral precursor TPB-S with thioethers groups,and then successfully constructed a new 3D COF(named3D-TPB-S-COF)through[4+4]imine condensation reactions.3D-TPB-S-COF was found to exhibit good crystallinity,porosity and stability.In addition,3D-TPB-S-COF was proposed to adapt five-fold interpenetrated pts topology through PXRD analysis and structural modeling.2.3D-TPB-S-COF was applied to the adsorption of Hg²⁺in water.The results showed that 3D-TPB-S-COF exhibited a good Hg²⁺adsorption capacity(588 mg·g^-1).And the adsorption kinetics experiment found that 3D-TPB-S-COF could remove more than 99%Hg²⁺in solution within 5 minutes.Furthermore,3D-TPB-S-COF could be used for at least three times with high adsorption performance.