| With the increase of global population and the aggravation of industrial pollution,the shortage of fresh water resources has become an important problem restricting the sustainable development of human society and economy.Solar interface evaporation desalination of seawater has attracted extensive attention of researchers because of its great application potential of using clean energy to purify water.Through the preliminary exploration of photothermal materials,evaporation water supply and heat management,the design of high-efficiency photothermal interface evaporator is studied.In recent years,metal nanoparticles,semiconductor materials,organic polymers and carbon based materials have been widely used in the field of photothermal evaporation and achieved some results.However,the problems of high material cost,complex preparation methods and low photothermal efficiency limit their large-scale application.At the same time,when the evaporator is used to desalinate seawater or purify wastewater,Metal salts or organic impurities in the water body may block the water supply holes and affect the evaporation efficiency and the recycling of photothermal materials.Therefore,it is very important to design a low-cost,simple preparation,high photothermal conversion efficiency and recyclable photothermal interface evaporator.Taking biomass and biomass waste as the construction unit,this paper designs a high-level high-efficiency interface evaporator.The specific research contents are as follows:(1)Preparation and photothermal properties of polymer coated radish based photothermal materials.Taking white radish as the substrate,dopamine or pyrrole was polymerized on the surface of radish by in-situ polymerization.The original honeycomb pore structure of radish was opened by vacuum freeze-drying to prepare polymer coated radish based photothermal material.Its light absorption performance,hydrophilic performance and evaporation stability were studied,Through a super absorbent paper and a low thermal conductivity polyethylene foam,a hierarchical interface photothermal evaporator was constructed to study the water transport,thermal management and photothermal conversion performance of the evaporator.The results show that the polymer coated radish based photothermal material has excellent properties.The light absorption capacity of radish modified by polypyrrole and polydopamine is as high as 98.12%and 85.63%.Stable photothermal evaporation can be realized under light,and the photothermal conversion efficiency is 98.97%and 89.01%respectively.(2)Preparation and photothermal properties of bagasse based aerogels.Biomass bagasse was used as raw material to produce carbon powder from some bagasse by carbonization and ball milling.Some bagasse was made into cellulose like compounds by hydrothermal reaction.The carbon powder and cellulose were mixed in different proportions.The photo thermal gels were prepared by cross-linking of sodium alginate and calcium chloride under the condition of real air freeze-drying.Two dimensional interface evaporator was constructed based on one dimensional strong absorbent cotton core and polyethylene foam as water conducting material and heat insulation material.The photo thermal performance,cycling performance,seawater desalination and purification ability of dye wastewater were studied.The results show that bagasse based aerogels have excellent photothermal properties and recycling performance.The three-dimensional network structure of aerogels can effectively reduce the latent heat of water evaporation.The evaporation capacity of the aerogel reaches 1.36Kg·m-2·h-1under a solar light intensity,and it has broad application potential in seawater desalination and dyeing wastewater purification. |
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