| To face the challenges of the water crisis,people are striving to find an efficient and low-cost desalination technology.Solar desalination uses solar energy as an energy source to achieve desalination through a distillation process by sequential evaporation and condensation.Solar energy is inexhaustible so that the solar desalination process has the advantage of zero pollution.However,the traditional solar distiller has suffered from a low light-to-heat conversion efficiency due to it belonging to body heating.In this case,majority energy is radiated in other ways during the heating process,resulting in low heat evaporation efficiency.Recent studies have shown that the interface heating process can effectively resolve this problem.A high absorbance light absorber is prepared by selecting a special light absorbing material as well as structureal design.Enable designing highly efficient absorber,the main research contents of this paper are as follows:1.GO solar absorber has been prepared by vacuum filfration using aporous hydrophilic polyvinyglidence fluorid as substrate and followed by reduction using hydrazine vapor.The morphology structure and absorbance of the absorber were characterized.The results show that varing the surface pore size of the rGO film from 1 μm to 220 nm,the evaporation rate firstly increased from 0.63 kg/m2·h-1 to 0.87 kg/m2·h-1 and then reduced to 0.76 kg/m2·h-1,indicating that the evaporation rate has related to microporous structure of rGO film.2.Inspired by the transportation process of water in plants,the rGO film is used as a photothermal absorber to improve the traditional photothermal conversion device.The evaporation rates under one sun illumination of pure water,traditional model and modified model are 0.55,0.84 and 1.26 kg/m2·h-1,respectively.Further,the photothermal efficiency of the modified model is increased from 48%to 74%Studies have shown that the loss of heat during transfer can be reduced using modified model and thereby the photothermal conversion efficiency can be greatly improved.3.The rGO@Ag composite has been synthesized by hydrothermal method,and preparatted rGO@Ag composite absorber.The morphology,structure,absorbance and desalting performance of the composite absorber were characterized.The rGO@Ag composite film exhibits local plasmon phenomenon at around 400 nm.The average absorbance of the composite film is 0.622 in the wavelength range of 200-2500 nm.The evaporation rate of rGO@Ag composite film was 1.31 kg/m2·h-1 and the photothermal conversion efficiency of 77.7%.Moreover,according to the sanitary standards of drinking water in China,the ICP test results show that water treated by rGO@Ag photothermal film meet the requirements of indicators of ions in drinking water in China. |
