【作者】 李爽；

【导师】 李祥村； 马艳勋；

【作者基本信息】 大连理工大学 ， 化学工程， 2024， 硕士

【摘要】 随着人口膨胀和环境污染日益加剧,淡水资源短缺问题亟待解决。太阳能驱动的界面水蒸发技术可以通过吸收太阳能实现持续的海水淡化和废水处理,被认为是解决淡水资源短缺的有效方法之一。其中,光热材料和水蒸发系统的结构设计与优化对太阳能水蒸发性能的提高尤为重要。针对太阳能水蒸发系统中光热材料的光捕获能力差、热损大及光热转换效率低等问题,本文以碳纳米管（CNTs）及其复合材料为光热转换材料,通过对水蒸发系统的结构调控实现高效、稳定的太阳能蒸发性能。主要研究内容如下:通过相转化法制备多孔碳膜（CNT@C）并探究了其在太阳能水蒸发中的应用。CNT@C膜以CNTs为骨架,其分级孔道结构为水分的运输提供了保障,并且CNT@C膜中CNTs具有良好的吸光性。以CNT@C-1膜为光热材料的隔离式水蒸发系统,在1个太阳光照射下,纯水的蒸发速率为2.35 kg m^-2 h^-1;在真实海水的测试中,CNT@C-1膜的蒸发速率为2.31 kg m^-2 h^-1,与纯水相近,表明材料具有较好的应用前景。为了提高材料对太阳光的吸收能力,利用水热法在CNT@C膜上引入双相MoS₂修饰其表面结构,提高水蒸发性能。MoS₂具有较高的吸光性,且花状MoS₂的引入使得CNT@C膜表面的粗糙度变大,增强了光在材料中的折射作用,提高了材料的光吸收能力。MoS₂-CNT@C膜具有良好的亲水性,并且蒸发系统采用一维水路通道进行供水,保证了水分运输的同时降低了从光热材料到主体水中的传导热损失。在1个太阳光的照射下,MoS₂-CNT@C-2膜具有2.53 kg m^-2 h^-1的纯水蒸发速率,光热转换效率为95.8%,传导热损失为1.28%。此外,样品在海水中的蒸发速率为2.51 kg m^-2 h^-1,并表现出良好的耐盐性和稳定性,此外,可提供高质量的淡水,具有实际应用的潜力。为了进一步降低生产成本,开发了具有高效水蒸发及淡化、净化水功能的MoS₂/CNT-PM膜材料。通过相转化法和水热法分别制备亲水性PAN膜和MoS₂/CNT材料,并将MoS₂/CNT材料喷涂在PAN膜上。MoS₂/CNTs复合材料具备良好的太阳光吸收能力,且多孔亲水的PAN膜可以保障水的持续运输。最后将PDMS喷涂在MoS₂/CNT材料上,在保护材料的同时使膜的上层具有疏水性,构建了亲水-疏水结构。在1个太阳光的照射下,纯水蒸发速率为2.27 kg m^-2 h^-1,海水蒸发速率为2.24 kg m^-2 h^-1,并且在连续光照12 h后膜表面没有明显的盐分析出,具有良好的耐盐性能。测试结果表明MoS₂/CNT-PM膜在海水淡化和废水处理中具有良好的应用前景。更多还原

【Abstract】 With the increasing population expansion and environmental pollution,the shortage of fresh water resources needs to be solved urgently.Solar-powered interfacial water evaporation technology can achieve continuous seawater desalination and wastewater treatment by absorbing solar energy,is considered to be one of the effective ways to solve the shortage of fresh water resources.Among them,the structural design and optimization of photothermal materials and water evaporation system are particularly important to improve the performance of solar water evaporation.Aiming at the problems of poor light capture ability,large heat loss and low photothermal conversion efficiency of photothermal materials in solar water evaporation system,carbon nanotubes（CNTs）and their composite materials were used as photothermal conversion materials in this paper,and efficient and stable solar evaporation performance was achieved through structural regulation of water evaporation system.The main research contents are as follows:Porous carbon films（CNT@C）were prepared by phase conversion method and their application in solar water evaporation was investigated.The CNT@C membrane was framed by CNTs,and its hierarchical pore structure provided a guarantee for the transport of water,and CNTs in the CNT@C membrane had good light absorption.In an isolated water evaporation system using CNT@C-1 film as photothermal material,the evaporation rate of pure water is2.35 kg m^-2 h^-1 under one sunlight irradiation.In the test of real seawater,the evaporation rate of CNT@C-1 membrane is 2.31 kg m^-2 h^-1,which is similar to that of pure water,indicating that the material has a good application prospect.In order to improve the solar absorption capacity of the material,the surface structure of CNT@C film was modified by introducing biphase MoS₂ by hydrothermal method,and the water evaporation performance was improved.MoS₂ has high light absorption,and the introduction of flower-like MoS₂ increases the surface roughness of CNT@C film,enhances the refraction of light in the material,and improves the light absorption capacity of the material.MoS₂-CNT@C film has good hydrophilicity,and the evaporation system adopts one-dimensional water channel for water supply,ensuring water transport and reducing the conduction heat loss from the photothermal material to the main water.Under the irradiation of one sunlight,MoS₂-CNT@C-2 film has a pure water evaporation rate of 2.53 kg m^-2 h^-1,the photothermal conversion efficiency is 95.8%,and the conduction heat loss is 1.28%.In addition,the evaporation rate of the sample in seawater is 2.51 kg m^-2 h^-1,and it shows good salt tolerance and stability,in addition,it can provide high-quality fresh water,and has the potential for practical applications.In order to further reduce the production cost,the MoS₂/CNT-PM membrane material with high efficiency water evaporation,desalination and water purification function has been developed.Hydrophilic PAN film and MoS₂/CNT material were prepared by phase conversion method and hydrothermal method respectively,and MoS₂/CNT material was sprayed on PAN film.MoS₂/CNTs composites have good sunlight absorption capacity,and the porous hydrophilic PAN film can ensure the continuous transport of water.Finally,PDMS is sprayed on MoS₂/CNT material,which makes the upper layer of the film hydrophobic while protecting the material,and constructs the hydrophilic and hydrophobic structure.Under the irradiation of one sunlight,the evaporation rate of pure water is 2.27 kg m^-2 h^-1,and the evaporation rate of sea water is 2.24 kg m^-2 h^-1,and there is no obvious salt precipitation on the surface of the film after 12 hours of continuous illumination,which has good salt resistance.The test results show that MoS₂/CNT-PM membrane has a good application prospect in seawater desalination and wastewater treatment.更多还原