| Traditional seawater desalination technology plays a key role in alleviating the increasingly serious crisis of fresh water shortage.However,they are hindered by high cost,high energy consumption and environmental pollution.In the past few years,the technology of solar driven interface evaporation water(solar steam generation)has developed rapidly.This technology uses solar energy to heat water to obtain steam,which can develop eco-friendly and cost-effective fresh water production,and meet the needs of energy and environment.This technology has attracted extensive attention and research,and has become a low-cost and promising desalination technology.Polyaniline is a kind of conductive polymer,which is easy to obtain as raw materials, has simple synthesis process,good chemical and environmental stability;at the same time,polyaniline can improve the hydrophilicity of materials,various morphologies and remarkable optical properties.Therefore,polyaniline should shine in the field of solar steam generation technology.In order to prove that polyaniline has excellent application potential in the field of seawater desalination,we have completed the following works for polyaniline:(1)Polyaniline nanofibers were loaded on the carbonized polyacrylonitrile fiber felt by high temperature annealing and electrochemical polymerization.Finally,a kind of carbon fiber cloth(ECFC/CPAW)loaded with carbonized polyaniline nanowires with low density,high solar absorption,good thermal insulation performance,high water transport efficiency and rich pore structure was obtained by annealing again.Under the addition of polyurethane foam,the evaporation rate can reach 1.4255 kg m-2 h-1,indicating 80.1%of photothermal conversion efficiency(1 kW m-2).In seawater desalination experiment,carbon fiber cloth coated with carbon polyaniline nanowires showed excellent desalination effect and good recycling performance.(2)Although the first work shows good photothermal conversion efficiency,it also has the following disadvantages:(1)annealing for two times makes the experiment process cumbersome,and increases the cost of experiments and utilization of resources;(2)the need for polyurethane foam helps increase the cost of raw materials and the complexity of evaporation structure.Therefore,based on melamine foam,a low-cost three-dimensional composite foam was prepared by the simple physical adsorption method based on the industrial polyaniline and porous carbon(prepared with low-priced sodium and ethanol).The composite foam has the ability of self floating,and the evaporation structure and the preparation process are all simplified.After many experiments,we determined an optimal mass ratio of porous carbon to polyaniline.The prepared composite foam had higher evaporation rate(1.496 kg m-2 h-1)and photothermal conversion efficiency(87.3%)under the same solar illumination.At the same time,the composite foam also showed excellent seawater desalination effect,durability and salt deposition resistance.In this study,we prepared two kinds of polyaniline based composite photothermal conversion materials.The two kinds of polyaniline based composite photothermal conversion materials have strong hydrophilicity,wide band and high efficiency of light absorption,high efficiency of photothermal conversion and excellent desalination ability,showing a good application prospect.Facts have proved that polyaniline has excellent application potential in the field of seawater desalination. |
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