Design And Application Of Solar Interfacial Evaporation System Based On Graphene-based Composite Foa

The lack of safe drinking water is one of the most daunting global challenges facing human society.Desalination is considered one of the most cost-effective ways to increase drinking water supplies.Currently,solar-powered desalination is emerging as one of the most promising technologies for increasing clean water supplies,as solar energy and seawater are abundant and have a negligible carbon footprint,especially for remote areas that lack electricity or infrastructure.In order to promote the further development of solar direct desalination technology,people have made great efforts in improving the efficiency of photothermal conversion,extending the life of equipment,and reducing the cost of solar desalination.However,for previous solar desalination units,while producing clean water vapor,there will be a large amount of salt accumulation on the surface,even in low-salinity environments.These deposited salts can seriously affect the absorption efficiency of incoming sunlight,and even block water channels.Therefore,in this paper,we are committed to exploring a simple and low-cost method to prepare efficient solar evaporators for desalination of seawater.In order to solve the problem that the evaporator cannot work continuously in high concentration brine,the GCPF-3 evaporator with excellent performance was obtained by loading graphene oxide,carbon nanotubes and polypyrrole onto the surface of the foam through simple steps such as polymerization,reduction and spraying with melamine foam as the skeleton.MF has a dense multi-space network structure,which can quickly transfer water and reduce the accumulation of salt inside the evaporator.Due to its excellent mechanical and optical properties,the evaporator has a high average evaporation rate(2.034 kg m^-2 h^-1)and a high solar steam generation efficiency（97.4%）during operation.In addition,the 3D GCPF-3 demonstrated surprising performance,being able to operate in brine up to24.5 wt%for long periods of times,and demonstrated evaporation rates far exceeding those of two-dimensional evaporators(4.174 kg m^-2 h^-1).The 3D GCPF-3 has demonstrated excellent structural stability and evaporation performance in more than 30 days of cycle durability testing,guaranteeing long-term durability and reusability.The great potential of 3D samples for salt tolerance and high rate evaporation was demonstrated.Most of the materials have problems with water supply limits,limiting the possibility of 3D sample preparation.The first work also had the defect of not being able to prepare 3D samples of higher height,limiting further improvement of sample performance.In order to solve the problem,a solar evaporator with excellent water supply,low cost,high evaporation efficiency and good mechanical properties was prepared by using pre-compressed melamine foam-supported graphene oxide through reduction,crystallization,freeze-drying and carbonization.Under a single sunlight irradiation,the evaporation rate can reach 2.41 kg m^-2 h^-1,and the evaporation efficiency is as high as 95.4%.In addition,the high water absorption of pre-compressed MF can continuously supply water to the evaporation interface,and the 3D graphene oxide foam prepared according to this feature can evaporate at a rate of 5.94 kg m^-2 h^-1 under a single sunlight.An original device for solar desalination under natural conditions is designed to prove its application possibility in real life.