Gold Nanoparticles Composites And Bionic,Salt Resistant Evaporation System Used For Stable And Efficient Solar Desalination

Fresh water is one of the most important issues concerning survival and sustainable development of human beings in the future.Extensive attention has been drawn to the solar evaporation system as it features sustainability and economy in seawater desalination.However,such a system is largely hindered by the poor photothermal conversion and slow evaporation speed.Furthermore,complex preparation of phothermal materials limits its large-scale preparation.Here,we conduct following researches to solve the problems above:Chapter 2:To minimize heat loss,a bionic system based on PP was designed.Such a system simulate the water transport mechanism in transpiration process of plant,with no direct contact between photothermal materials and bulk water,enabling enhanced heat localization around evaporation surface to maximize evaporation efficiency.The efficiency of bionic system was 89%under 10 sun and 79%under natural sunlight.Thus,high evaporation speed and efficiency were realized by bionic system under both concentrated and natural sunlight.Furthermore,to simplify the preparation of gold nanoparticles?GNPs?composite materials,a plate thermal reduction?PTR?method was raised to prepare plasmonic–active filter paper?PP?.PP was prepared in rapid manners,without the pre-preparation of GNPs colloids.As-prepared PP possessed poly-disperse GNPs,which supports intensive and broadband solar absorption to make the most of solar radiation?92%?.Chapter 3:Systems based on interfacial evaporation bring serious problems of surface salt deposition,which decreases solar energy utilization.Herein,melamine resin sponge?MRS?was chosen to enable a self-driven salt resistant mechanism.Benefiting from the particularly powerful water absorption of MRS,the seawater was spontaneously pumped up by capillary force.During evaporation,seawater was concentrated to brine with higher density,and the 3D porous fiber structure provided a free exchange space to equalize the salinity inside the sponge.As such,the solution in the evaporation zone remained under saturated,fundamentally avoiding generation of solid salt.The MRS was made into BGNPs-deposited sponge?BDS?to fully utilize solar energy,with solar absorption 96%.BDS can maintain an efficiency of 90%for 11 hours under 10 sun and an efficiency of 80%for at least 4 days under natural sunlight,with no visible salt deposition.Chapter 4:Considering that fresh water can only be obtained when the generated steam condensated,we designed a large-scale solar still based on BDS evaporator to get actual fresh water.The fresh water output was reached 5.9 kg m^-2 d^-1,and the collection rate was up to65.1%,and we further optimize relevant parameters that will affect fresh water output.