Study On The Construction Of MOF Containing Electrospun Materials For The Adsorption Of Typical Pollutants From Water

With the development of global technology and industrialization,a large number of chemicals continue to enter the environment of human life.These chemicals have the ability of difficult biodegradation and environmental durability,and are harmful to human health.It is particularly important to develop a water treatment adsorbent with simple preparation,high efficiency,low price and renewable recycling to remove typical pollutants in water.Metal-organic framework（MOF）,as a new water purification adsorbent,has shown great potential in the field of water purification applications due to its large specific surface area,high porosity,good thermal stability and adjustable pore structure.However,the inherent natural brittleness and powder state of MOF crystal hinder its processability and practicability,and limits its practical application in the field of water purification.Therefore,it is an effective solution to integrate functional MOF into various matrices to prepare formable and high-performance macro composites.In this thesis,the content of MOF in the composite is increased by blending MOF or in-situ growing MOF.Introducing electrospun materials into composite adsorbent not only improves the dispersion of MOF in the composite material,but also ensures the stability of the composite material itself.Furthermore,a series of MOF-based composite adsorbent with different components and structures are constructed.Taking typical water pollutants such as antibiotics,metal ions,pesticides and dyes as target pollutants,the adsorption performance,renewable recycling and universality of different MOF-based composite adsorbents for the removal target pollutants were systematically studied.The main research contents are as follows:1.ZIF-8/PAN electrospun nanofiber membrane with self-supporting and flexibility was directly prepared by blending MOF method and electrospinning technology.By controlling the mass content of ZIF-8 nanoparticles,a series of ZIF-8/PAN electrospun nanofiber membranes with different content of ZIF-8 were prepared,and the maximum addition of ZIF-8 was 59.89%.As one of the representative antibiotics,TC is selected as the adsorption model,and the adsorption capacity of ZIF-8/PAN nanofiber membrane can reach 255.92 mg·g^-1.More importantly,this method can be extended to the preparation of other MOF-based electrospun nanofiber membrane adsorbent（such as MIL series and Ui O series）.2.The Ui O-66-NH₂/PAN nanofiber/chitosan（Ui O-66-NH₂/PANNs/CS）aerogel with three-dimensional（3D）structure,ultralight,compressible,multi-layer pores and high adsorption capacity was prepared by the combination of blending MOF method,chemical crosslinking method and freeze-drying technology.MOF nanofiber aerogel retains the characteristics of the original Ui O-66-NH₂,such as large surface area and high porosity.The addition of electrospun nanofibers solves the brittleness problem of pure chitosan aerogel and makes the pure chitosan aerogel compressible.Ui O-66-NH₂/PANNs/CS aerogel maintains the micropore and accessibility of Ui O-66-NH₂,and its specific surface area reaches 326.51 m²·g^-1.In the experiment of further removing Pb（II）from wastewater,the saturated adsorption capacity of Ui O-66-NH₂/PANNs/CS aerogel for Pb（II）was 113.64mg·g^-1.3.The one-step self-crosslinking strategy was adopted to design a 3D macroporous MOF nanofiber aerogel with high adsorption capacity,and the MIL-101（Cr）/PAN nanofiber/agarose（MIL-101（Cr）/PANNs/AG）aerogel with self-supporting property,underwater compressibility,multistage pores and high adsorption capacity was successfully prepared.The formation of aerogel depends on the self-crosslinking of hydrogen bonds between molecules without any chemical crosslinking agent.The addition of electrospun fiber improves the structural stability and immersion stability of agarose aerogel,and makes it compressible in immersion.MIL-101（Cr）in the composite aerogel retains good micropores,which endows the composite aerogel with excellent absorption capacity in water purification.MIL-101（Cr）/PANNs/AG aerogels were systematically characterized and tested,and their adsorption properties for 2,4-Dichlorophenoxyacetic acid（2,4-D）were studied.When the mass load of MIL-101（Cr）nanoparticles is 50%,the specific surface area of the MIL-101（Cr）/PANNs/AG aerogel reaches 356.91 m²·g^-1 and the equilibrium adsorption capacity of 2,4-D reaches 339.87 mg·g^-1,indicating that the aerogel has high adsorption capacity.4.The carrier unit was constructed by electrospun fiber and regenerated cellulose（RC）,and then MOF was in-situ grown on its surface.The MOF/electrospun fiber/regenerated cellulose（HKUST-1/PANNs/RC）aerogel with 3D multi-layer pore structure,high specific surface area and high adsorption capacity was successfully prepared.The results showed that under extreme synthesis conditions（high-temperature and high-pressure p H=2.8）,HKUST-1 was in-situ grown on aerogel by solvothermal method,and the mass loading rate of HKUST-19 in HKUST-1/PANNS/RC aerogel reached 42.06%,the specific surface area reached 639.3 m²·g^-1,and the equilibrium adsorption capacity for methylene blue（MB）reached 522.01 mg·g^-1.