Study On Characteristics Of Graphene Oxide Composite Membrane And Its Application In Desalination Water System

With the rapid development of society and science and technology,the demand for energy increases year by year,and the consumption of traditional fossil energy makes environmental problems more and more prominent.As a kind of clean energy,solar energy has great development prospect.According to the problems faced by the traditional seawater desalination technology.In recent years,because of its high photothermal conversion efficiency and excellent evaporation performance,solar thermal local seawater desalination technology has become a research hotspot.In this paper,the structure of composite film and evaporation system is innovated.A variety of factors affecting the evaporation rate and efficiency of the evaporation system were explored.Based on the composite film,a seawater desalination solar room device was designed and the evaporation performance of the system was tested.Firstly,this paper prepared GO by Hummers method,characterized the original graphite and prepared GO,They include scanning electron microscopy(SEM),transmission electron microscopy(TEM),UV-visible absorption spectroscopy(UV-Vis),Fourier infrared spectroscopy(FT-IR),Raman spectroscopy(Raman)and X-ray diffraction(XRD).The graphene oxide(GO)composite films were prepared by vacuum filtration.The microstructure,characteristic peaks,hydrophilicity and mechanical strength were observed.In the evaporation system,a new water channel is developed,which attracts water to the top of the absorber through capillary action,and water wetting the surface of the absorber to achieve the purpose of water supply.New water channels can increase evaporation rate and reduce heat loss.Secondly,based on the prepared composite film and the new water channel,the relationship between various factors and evaporation efficiency was explored,involving variables such as the thickness of insulation layer,the selection of water channel,the intensity of illumination and the concentration of salt solution.Seven thickness gradients of 0.2-2.4 cm were set to test the evaporation rate,and the insulation layer thickness with the best evaporation efficiency was obtained.The evaporation system was selected as 600,700 and 800 W·m^-2,and the evaporation rate was compared.Three kinds of irradiance were obtained by comparing the two dimensional and three dimensional water channels,and the change rules of the surface temperature,evaporation mass change and evaporation efficiency of the composite film were obtained.In the experiment,salt solutions of different concentrations were prepared,and seven groups of Na Cl solutions of 3.5,7,10.5,14,17.5 and 21%were tested.The variation of surface temperature of the composite film with time was obtained.During the preparation process,the composite films prepared by adding 0.5,1.0,2.0,4.0 and8.0 mg GO were respectively added to obtain the cumulative change of evaporated water,the change rule of the surface temperature of the composite film with time,and the change rule of the evaporation rate and evaporation efficiency with the increase of GO mass.Based on the above experiments,the composite films with low cost,simple preparation,good mechanical properties and strong desalination ability were obtained.The evaporation rate and efficiency of the composite film increased with the increase of solar irradiance,and reached 1.45 kg·m^-2·h^-1 and 92.5%,respectively,under the sunlight irradiation of 1000 W·m^-2.The new composite film can be used in solar evaporation system to improve the evaporation efficiency.Finally,the composite film combined with the new solar interface evaporation solar room model was tested.Based on the working principle and test scheme,the relationship between solar irradiance and evaporation rate in natural environment was obtained,and the feasibility of composite film in interfacial evaporation system was explored.If the effective coverage area of the solar interface evaporation system on the roof can reach 70 m² or above,it can meet the daily average domestic water consumption of a family of three people under normal working conditions.The graphene oxide composite film was applied to the solar interfacial evaporation system.The technology can be widely extended to seawater,fresh water,green building,low carbon human settlements and other fields.