| Clean freshwater resources are closely related to many aspects of human survival and social development,such as industry,energy and food production,ecological balance and so on.The problem of water shortage is becoming more and more serious due to the rapid growth of population and the development of economy.Therefore,how to efficiently obtain fresh water resources has become the focus of current research.At present,the mainstream approach to obtain fresh water resources are the membrane method and thermal method,they are all very mature method of large-scale access to fresh water resources,but these two solutions are need to consume large amounts of fossil fuels,inevitably caused certain pollution to the environment.In recent years,solar desalination through the air-water interface provide a new method to solve this problem.The key of the method is to prepare the light absorbing materials and then absorb the sunlight and convert it into heat.In order to prepare the low cost and high efficiency of light absorbing materials,the following work have been done in this paper:(1)WO3 nanorods was synthesized by hydrothermal method,and then annealed at 500?under the Ar/H2 atmosphere with different time to prepare the WO3-x nanorods,finally soluble in water to form the solution and evenly coated on the wood surface to prepare the evap orator.Due to the localized surface plasmon resonance effect(LSPR)of the WO3-x nanorods and the multiple scattering properties of wood,WO3-x-2h evaporator could absorb 94%of the sunlight,the evaporation rate of seawater can reach 1.28 kg·m-2·h-1,and achieve the photothermal conversion efficiency of 82.5%under 1 sun illumination.The fresh water obtained after desalination is far below the standards of the WHO.In addition,it also shows good desalination characteristics for simulating heavy metal ions and industrial dye wastewater.(2)W18O49 was synthesized under different hydrothermal temperature using the WCl6 and C2H6O as raw materials.The morphology of the W18O49 prepared at 180? exhibites seaurchin like structure,moreover,it has higher surface area and stronger light absorption ability than others,so we prepared the W18O49/rGO heterostructure under the condition of 180? by adding different contents of GO,and then dissolved in the water evenly coated on the surface of wood to prepare the evaporator.Due to the LSPR effect of W18O49,the strong light absorption ability of the rGO and the comprehensive effect of heterostructure,the W-W18O49/rGO-0.01 evaporator could absorb 97.07%of the sunlight,the surface temperature can rise to 64.0? under 1 sun illumination,the water evaporation rate can reach 1.34 kg·m-2·h-1 and achieve the solar-thermal conversion efficiency of 86.5%,which is higher than most of the reported literatures.In addition,the ions concentration significantly reduced after desalination,which can satisfied the standard of drinking water.(3)The Ni-G was prepared by chemical vapor deposition(CVD)method using porous Ni as the carrier,and then it was used to prepare the Ni-G-WO3-x under hydrothermal conditions.Then it was in conjuction with the cotton wick wrapped polystyrene(PE)foam and floated on the water surface,the cotton wick could transport the water,the PE foam could serve as the thermal insulating layer,and the Ni-G-WO3-x could absorb sunlight and convert it into heat energy,the strong light absorption properties of the graphene and WO3-x as well as the multiple scattering of porous structure makes it absorbs 93%of the solar energy,Under the simulated sunlight intensity of 1 kW·m-2,the water evaporation rate can reach to 2.12 kg·m-2·h-1,which is 4.56 times higher than that of pure seawater(0.465 kg·m-1·h-1),and the photothermal conversion efficiency can reach 85%.In addition,the evaporator also shows excellent evaporation characteristics under outdoor conditions,which demonstrates that it has a great potential alternative for practical application in the future.(4)WS2 black light absorption material was prepared by ball milling and thermal reduction method using the WO3 and S powder as the raw material.Then the PVDF/WS2 porous membranes were fabricated through the nonsolvent-induced phase inversion process by changing the contents of WS2.The PVDF/WS2 membrane in wet conditions could absorb the sunlight of 90.58%when the WS2 content in the membrane is 0.2 g.The water evaporation rate can reach 1.30 kg·m2·h-1 with the evaporation efficiency of 80.5%under 1 sun illumination,and the surface temperatures can reach 76.2? under 5 sun illumination,which shows the strong ability of solar-thermal conversion,morevoer,due to the hydrophobic properties of the membrane,the cycle stability is greatly increased,and the membrane surface are no obvious salt after desalination. |
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