Preparation Of New Interface Photoevaporation Materials And Study Of Their Seawater Desalination Performanc

With the continuous development of the maritime transport industry,the demand for freshwater resources from ocean-going ships,offshore platforms,remote islands,and other areas has gradually increased.As an important guarantee for the life and health of maritime personnel and the normal operation of maritime equipment,researching high-quality freshwater acquisition methods has become an important development direction in the maritime transport industry.Interfacial solar desalination technology uses the principle of photothermal conversion to achieve evaporation of seawater at the air-water interface,which is expected to provide a new way to obtain freshwater resources with high quality.However,traditional interfacial solar desalination materials have problems such as high production cost,complicated preparation process and low evaporation efficiency.Therefore,this thesis introduces low-cost porous media and prepares photothermal conversion materials with excellent photothermal conversion performance based on green,simple and efficient solution impregnation modification method and solvent volatilization modification method.Moreover,this thesis also explores the influence law of different substrate materials and mixed solution composition on the evaporation efficiency of desalination materials,and realizes the preparation of interfacial photoevaporation materials without the limitation of material intrinsic properties,which provides a new solution for desalination.A two-dimensional iron tannate modified cotton fabric composite film interfacial photoevaporation material（Fe-PCP）was prepared by using a simple and scalable solution impregnation modification method,selecting low-cost and environmentally friendly cotton fabric as the substrate,and using tannic acid complexed with iron chloride to produce black iron tannate photothermal conversion material as the light absorbing layer to achieve twodimensional photoevaporation.The prepared Fe-PCP has good wettability,high light absorption of more than 90%in the visible and UV regions,and excellent cycling stability.The evaporation rate of Fe-PCP evaporation material reached 1.2 kg m^-2 h^-1 under one solar light intensity,and the evaporation efficiency reached 78.1%,which solved the problems of complicated preparation process,poor durability and low reliability of practical application of traditional interfacial photoevaporation materials.Using a green and controlled solvent volatilization modification method,a sponge with high porosity and good thermal insulation was selected as the substrate,and a controlled adjustable hydrogel layer was formed on the surface of the sponge skeleton by adjusting the intermolecular hydrogen bonding between tannic acid and polyvinyl alcohol through ethanol,and a black photothermal conversion layer was generated in situ on the surface of the hydrogel sponge skeleton by using the complexation reaction between iron chloride and tannic acid to prepare a three-dimensional iron tannate sponge interfacial photoevaporation material（Fe-PTPU）,which realized three-dimensional photoevaporation.The prepared FePTPU has ultra-high porosity and excellent light absorption in the full spectral range.Under one solar light intensity,Fe-PTPU achieves an evaporation rate of 2.65 kg m^-2 h^-1 with an evaporation efficiency of 90.17%,and has excellent mechanical and chemical stability,which solves the problems of low evaporation rate and poor scalability caused by plugging of traditional hydrogel-modified porous materials.The problem of low evaporation rate and poor scalability due to plugging of traditional hydrogel modified porous materials is solved.The two interfacial light evaporation materials prepared in this paper have good scalability,and the ion removal rate of water after desalination is 99.9%,which meets the WHO standard for drinking water.