Preparation Of Hierarchical Porous Pollen Derived Photothermal Material And Its Water Evaporation Performance

Solar thermal water evaporation is a sustainable solution to water and energy shortage.However,most evaporators still have the problems of low efficiency of conversion heat and high design cost.In recent years,interfacial water evaporation has become a hot topic of researcher.The conversion efficiency of photothermal evaporation system has been greatly improved by using efficient photothermal materials,excellent thermal management and great water transport.In this paper,the biomass carbon cell is prepared from natural rape pollen that was used as the photothermal conversion material,and the evaporation structure was carefully designed by using polymer materials to study its desalination performance.Some research achievements have been made:CuCl₂activation effectively increased the light absorption rate of pollen carbon cells from 82.6%to 90.1%.The sandwich photothermal evaporation device forms an integrated thermal management mechanism,which not only restricts the downward conduction of heat by inhibiting the excess water transport,but also builds a thermal insulation layer above the light absorption layer to reduce the convection and radiation of heat to the air without affecting the light absorption.This general thermal management strategy enables evaporation systems to achieve evaporation rates of up to 1.87 kg m^-2h^-1,and increases the energy conversion efficiency from 61%to 89.0%,far superior to other carbon-based and wood-based systems.Moreover,the constructed sandwich membrane also exhibits excellent self-regenerating performance in simulated seawater and high salinity water.The developed device can maintain an average evaporation rate of 4.3 L m^-2day^-1in a 25day consecutive outdoor test.Plasma copper was fabricated on the surface of Cu-PC by in situ catalytic growth method as an efficient solar absorber for solar steam generation.In the test of liquid temperature,Cu_1.0-PC showed excellent photothermal conversion performance,the conversion efficiency of 93.43%was much higher than that of Cu-PC（86.83%）.Through careful study of internal stress and electron transfer,the interaction mechanism of Cu/carbon interface was revealed,and it was found that free electrons in the Cu/carbon interface would spontaneously transfer from carbon to copper,thus achieving the purpose of protecting Cu particles.Additionally,the self-sedimentation of carbon cells allows the easily concentration of solar absorbers at the evaporation surface of polyvinyl alcohol hydrogel to improve heat localization and cut down the usage of solar absorbers to a half.Heavy metal ions and organic dyes can be effectively removed due to the superior adsorption capability of the carbon cells and the formation of hydrogen and chelating bonds with the numerous hydroxyl groups of hydrogel network.