Study On Preparations And Application Of MOF Coating On Substrate Surface

Due to the advantages of metal-organic frameworks with diverse structures,controllable pore sizes,modifiable pore surfaces,and high specific surface area,MOFs have shown great potential in applications such as gas adsorption,separation,catalysis,and sensing.However,since MOFs are usually synthesized as crystalline powders,their processing is limited,which is not conducive to the industrial application of MOFs.There is an urgent need to shape MOFs into different forms such as pellets,coatings,and paper sheets,while retaining or improving their properties for easy processing,handling,and storage.Shaping the MOF into different forms can also make it suitable for more diverse application scenarios.As an extension of the design and synthesis,the forming technique of MOF is of great significance for the practical application of such porous materials in the future.In this dissertation,a variety of Cu-MOF coatings were grown in situ on the surface of Cu substrates by two electrochemical synthesis methods,electro-displacement deposition and anodic deposition,respectively.A variety of Zr-MOF coatings were grown in situ on the surfaces of various pre-modified supports by using the solvothermal synthesis method of uniform heating and local heating.And combined with a variety of characterization techniques to characterize the formed MOF materials.The Glass Fabric@UiO-67 prepared by solvothermal method was used for the adsorption and extraction of atrazine,bentazone and tebuconazole.Combined with IMS,the on-site rapid detection of the target was achieved.The results achieved in this paper are as follows:（1）Preparation of Cu-MOF on the copper surface by electrodisplacement deposition method:The Cu²⁺required for the formation of Cu-MOF is released near the surface of the metal Cu surface using an oxidant,and then reacts with the ligands in the mother solution to form Cu-MOF on the metal surface coating.Taking Cu-BTC as the representative of Cu-MOF,the effects of different oxidants and solvents were explored,and the results showed that the combination of Fe Cl₃/H2O and Fe Cl₃/DMSO was the best.By further optimizing the oxidant concentration,a highly dense and uniform Cu-BTC MOF coating was successfully prepared on the surface of foamed Cu.It is worth mentioning that the Cu-BTC under Fe Cl₃/H2O condition presents an atypical cubic morphology,and its XRD pattern shows that although the morphology is special,it is still a pure Cu-BTC phase.Using the optimal Fe Cl₃ concentration of Cu-BTC,three kinds of Cu-MOF coatings were further prepared in DMSO,namely Cu（BDC）-MOF,Cu（BDC-NH₂）-MOF and Cu（INA）₂（H₂O）₄-MOF coating,expanding the scope of application of the electro-displacement deposition method.（2）Preparation of Pillar-Layer Cu-MOF on copper surface by anodic deposition:Pillar-Layer MOF with interpenetrating structure is widely used in catalysis and gas separation due to its extremely flexible dynamic pore structure.In this paper,six kinds of columnar Cu-MOFs were prepared by electrochemical method for the first time.The Cu electrode is used as the source of Cu²⁺,and the electrode is placed in a solution of mixed ligands.By applying an appropriate voltage,the anode Cu is partially electrolyzed,and the Cu2+required for the formation of the columnar Cu-MOF is released on the anode surface,and then Immediately react with the ligands in solution to form a columnar Cu-MOF coating on the anode surface.Cu₂（BDC）₂（BPY）was selected as the representative of the columnar Cu-MOF.After optimizing the voltage,a dense and uniform Cu₂（BDC）₂（BPY）MOF coating was successfully prepared on the surface of the foamed Cu substrate;here On the basis of the optimal voltage,the optimal voltages of other columnar Cu-MOFs were obtained respectively,and five kinds of columnar Cu-MOF coatings were successfully prepared on the surface of the Cu substrate,namely Cu₂（BDC）₂（BPEE）,Cu₂（BDC-NH₂）₂（BPY）,Cu₂（BPDC）₂（BPY）,Cu₂（2,6-NDC）₂（BPY）,and Cu₂（2,6-NDC）₂（BPEE）.Expanded the scope of application of the anodic deposition method.（3）Preparation of Zr-MOF on the carrier surface:NH₂-UiO-66 and UiO-67 Zr-MOF were supported on the surface of cotton,silk and glass cloth by solvothermal method.Alkali-treated and seeded Zr⁴⁺cotton fibers,degummed silk fibers after sericin removal,and alkali-treated glass cloth with exposed surface hydroxyl groups were added as carriers to the mother solution of solvothermal synthesis of Zr-MOF.The Zr-MOF coating was grown in situ on the surface of the carrier,and the Zr-MOF grains were all attached to the surface of the three carriers,which were dense and uniform,and had a large loading capacity.The addition of cotton fiber and silk fiber makes the Zr-MOF grains tend to be more spherical.（4）Local heating deposition of UiO-67 coating:Select Ni Cr alloy wire with a diameter of 200μm,place it in the mother solution of UiO-67solvothermal synthesis,connect power at both ends,and use the electrothermal effect of Ni Cr alloy wire,forming a local high temperature near its surface,promoting the in-situ growth of UiO-67 on Ni Cr alloy wire.By optimizing the current intensity applied to the heating wire,a dense and uniform UiO-67coating was successfully prepared on the surface of the Ni Cr alloy wire.（5）An analytical method（Glass Fabric@UiO-67-IMS）for on-site adsorption extraction and detection of atrazine,bentazone and tebuconazole was established.The Glass Fabric@UiO-67 obtained by solvothermal deposition was used as an adsorption extraction membrane,and the pesticides in the water were subjected to adsorption extraction and then directly inserted into the IMS injection port for detection.The three pesticides showed good resolution on IMS.Under the optimal extraction conditions,the detection limits of the three pesticides were between 10μg L^-1 and 30μg L^-1.The actual water samples were spiked and analyzed,and the recoveries were between 81%and112%,which verified the applicability of the method.The Glass Fabric@UiO-67-IMS analytical method has short detection time and simple operation,and can potentially be applied to on-site water quality screening and detection of pesticide-contaminated environments.