有机-无机杂化光热转换无纺布的合成、性能调控及在太阳能淡化海水中的应用

The shortage of fresh-water resources impels the development of seawater-desalination technologies. Among these seawater-desalination technologies, solar-powered distillation has drawn much attention, and its key is to develop the porous membranes with low-cost, large-area, broad-band photoabsorption, high photothermal conversion, easy decontamination and recycling features. To address this problem, this project aims to design and prepare organic-inorganic hybrid photothermal nonwoven cloths for the solar-powered seawater desalination. This project includes four steps. The first step is to prepare several kinds of inorganic nanomaterials with broad-band photoabsorption and efficient photothermal effect, and to disperse these nanomaterials into polymer spinning solution which is then used to synthesize flexible and large-area organic-inorganic hybrid nonwoven cloths by electrospinning method. The second step is to measure and optimize the optical, photothermal, anticorrosion and launderability properties as well as long-term stability of these nonwoven cloths. The third step is to design and construct several distillation components consisting of nonwoven cloth and heat-insulation layer, to investigate their water-absorption rate/thermal-barrier effect and the heat-utilization/water-evaporation efficiency under sunlight illumination, and then to select efficient distillation components. The last step is to use the selected distillation component for assembling the inclined solar stills, and to test/optimize the evaporation-rate of seawater and production-rate of fresh water for realizing the efficient and long-term seawater desalination. This project will not only lay a foundation for the development of organic-inorganic hybrid nonwoven cloths with high photothermal effect, but also make important contributions to the practical application of solar-powered seawater desalination technology as well as the future reduction of the fresh-water crisis.

淡水资源短缺促使人们研发海水淡化技术，其中太阳能蒸馏法吸引了高度关注，其关键是开发低成本、大面积、宽光谱吸收、高效光热转换和便于清洗回收的多孔膜材料。本项目旨在设计和制备有机-无机杂化光热转换无纺布，并将其用于太阳能淡化海水。主要内容包括：1)制备几种具有宽光谱吸收和优异光热性能的无机纳米材料，将它们分散到高分子纺丝液中，再利用静电纺丝技术制备柔性大面积的无纺布；2)测试和优化无纺布的光学、光热转换、耐腐蚀和耐清洗性能以及长期稳定性；3)设计和构筑基于隔热层-无纺布层的蒸发组件，测试其吸水速度、隔热性能以及太阳光照射下的热利用率和水蒸发速度等，遴选高效的蒸发组件；4)利用蒸发组件组装倾斜幕芯式太阳能蒸馏器，太阳光照射下测试和优化海水蒸发和淡水产水率，实现长期高效地淡化海水。本项目的成功实施将为发展高效光热转换无纺布奠定基础，也为太阳能淡化海水技术走向应用和将来缓减淡水危机做出重要贡献。

太阳能海水淡化技术吸引了高度关注，其核心是发展宽光谱响应的光热转换膜材料以及高效的蒸发装置。目前，该领域已经取得了很多进展，但还存在蒸发速度不理想、析盐后性能下降、太阳光不能充分利用等问题。为解决以上问题，本项目旨在设计和制备宽光谱响应的有机-无机杂化光热转换布，并构筑新型高效蒸发装置。主要成果有：(1) 利用静电纺丝技术合成了碳纳米管(CNT)@聚丙烯腈(PAN)无纺布，发展了CNT墨水并染色了棉布；这些布展现了较好的光吸收和光热转换能力；随后构筑漂浮模式海水蒸发装置；蒸发过程会析出盐晶体，可通过简单手洗方式来除去盐；(2) 为避免手洗，发展了CsxWO3修饰的棉布，并设计了上下对称蒸发组件，可通过翻转方法进行自我清洁，实现了长时间高效蒸发；(3)为避免析盐，制备了聚苯胺纳米棒修饰的棉布，并组装了悬挂型太阳能海水蒸发装置，实现了高效热利用和双面蒸发，蒸发速度达到1.94 kg m-2 h-1；同时浓缩的卤水从悬挂织物的底部滴下；(4)为充分利用太阳光，利用静电纺丝-原位硫化技术制备了多级结构PAN@CuS杂化无纺布，该无纺布展现了较好的光吸收、光热转发性能以及较低的水蒸发焓，随后组装了向光模式蒸发器，在倾斜的阳光下(倾斜角从-90°到+90°)，蒸发率保持在~2.27 kg m –2 h –1，长时间蒸发不析盐。另外，发展了其它类型光催化和光热转换纳米材料，探索了它们在环境净化、变色服装、光热诊疗等方面的应用。项目负责人以通讯作者身份在Adv. Funct. Mater.、ACS Nano、Chem. Eng. J. 等重要期刊上共发表SCI论文28篇，其中影响因子大于10的论文有12篇；申请专利6项，其中授权专利有4项；多次入选高被引学者；荣获国家级青年人才计划、上海市自然科学一等奖(排名第二)、宝钢优秀教师奖等。