Study On The Construction And Properties Of Solar Water Evaporator Based On ⅣA Nanophotothermal Materials

Solar evaporation plays an important role in low energy freshwater production,which is essential for human health and economic development.In recent years,solar-driven interfacial water evaporation has been regarded as a new method to replace traditional water evaporation,which has attracted extensive research attention because of its high solar energy conversion efficiency and industrial potential.Photothermal conversion materials are the key of solar evaporation system.In this thesis,carbon and germanium nanoparticles in groupⅣA are used as photothermal conversion materials to construct solar water evaporators which can be used to obtain fresh water.The main contents and results are as follows:（1）The solar water evaporator based on graphene nanosheets was successfully prepared by using graphene nanosheets as photothermal conversion material and loaded onκ-carrageenan hydrogel surface by coating method.Graphene nanosheets are a good photothermal conversion material with large specific surface area,high mechanical strength,strong adsorption capacity and high solar absorption rate（86.66%）.When the coating amount of graphene nanosheets reaches 4 mg·cm^-2,the evaporation rate of the evaporator reaches 1.65kg·m^-2·h^-1 under one solar irradiation.The evaporator can effectively carry out seawater desalination and sewage purification,and has a certain salt resistance.（2）A solar water evaporator with high evaporation stability,high evaporation efficiency and excellent salt resistance was constructed by combining graphene oxide nanosheets,photothermal conversion material,with polyvinyl alcohol.In the process of illumination,partial photoreduction occurs in the GO nanosheets in the evaporator,and the solar spectrum absorption of partially reduced GO can reach 92.97%,which enhances the evaporation efficiency of the evaporator to a certain extent,and forms a self-enhanced evaporator that blends GO and partially reduced GO（PRGO）.The solar water evaporator based on PRGO nanosheets can achieve a high evaporation rate of 3.24 kg·m^-2·h^-1 and an energy efficiency of99.98%under one solar irradiation.The evaporator exhibits outstanding desalting and purification performance in seawater and sewage,and has excellent salt resistance.（3）Using germanium nanoparticles as photothermal conversion materials,the solar water evaporator based on germanium nanoparticles was successfully prepared by coatingκ-carrageenan hydrogel.Germanium is an excellent photothermal conversion material with a solar absorption rate of 92.33%.By virtue of the excellent photothermal conversion performance of germanium nanoparticles and the hydrophilicity and microporous water transfer channel ofκ-carrageenan hydrogel,the evaporator achieves a high evaporation rate of 2.88 kg·m^-2·h^-1 and an energy efficiency of 82.65%under one sun irradiation.The evaporator based on germanium nanoparticles shows good purification performance in seawater and sewage and excellent salt resistance.