高效一体化可循环使用的太阳能海水淡化石墨烯材料研究

As a clean, low cost and environmentally friendly approach, solar desalination has been considered as a promising solution to address the issue of water shortage. The solar desalination material is the key point for its application. Most of the solar desalination materials still exhibit the challenge to achieve more excellent performance, such as low efficiency under ambient sunlight, the poor stability/reusability and the complexity of the materials. These shortages limit the practical application. As such, this proposal aims to achieve a standalone three-dimensional bulk graphene material for solar desalination. A series of solar-steam materials will be designed and synthesized with various micro-nano structures and wettability to regulate the optical, thermal property and water supply. Such standalone three-dimensional graphene material with high absorption, low thermal conductivity and water channels could enhance the efficiency of the energy conversion and the stability/reusability. Moreover, the structure-function relationship and the solar-steam mechanism could be investigated and defined by studying the structural features and the properties of the designed materials. The completion of this proposal could enrich the insight into the light absorption, heat transfer, water transport and evaporation during the conversion process and provide useful research basis and theory for developing the application of solar-steam conversion for desalination with desired performance.

太阳能海水淡化技术具有清洁、低成本、环境友好等优点，拥有巨大的应用前景。其所使用的转换材料是决定该技术能否实际应用的关键，然而目前太阳能海水淡化材料存在自然光照强度下能量转换效率低、循环使用性差和拼接结构设计复杂等问题，限制了其推广应用。本项目拟构筑一种一体化太阳能海水淡化石墨烯材料，通过调控材料孔洞与片层次级微纳结构来增强其吸光性能，优化表面性能调控材料的亲水程度与亲水区域以解决隔热和水通道难以两优的问题；获得兼具高吸光、低热导和良好水传输性能、自然光照强度下具有高能量转换效率、可循环使用的三维石墨烯宏观体相材料；研究揭示材料结构性质与光蒸汽转换性能之间的构效关系，探索光蒸汽转换机理，增强对光吸收、热传导、水传输与蒸发过程的认知。本项目将为发展高性能太阳能海水淡化材料提供新策略，为其实际应用提供理论支撑。

界面型太阳能海水淡化技术因具有节能及效率高等优势，被广泛地认为是一种可以有效解决淡水资源短缺的技术手段。然而，在开发材料的过程中，在同一材料中能够同时满足降低热损失并且保证有效水通道是一项具有挑战性的工作，也因此限制了其发展。在本项研究中，我们发展了一种可以独立使用、自由漂浮的、Janus结构的3DG材料以及一种亲水性可控的紫外臭氧处理方式。通过上述亲水化处理，三维石墨烯的上层表现出亲水性，可以提供持续以及有效的水蒸发源；底层展现出疏水性，可以支撑材料漂浮在水面上以保证有效的光吸收并且减少热量的损失。得益于上述材料结构的协同左右，Janus 3DG在一个太阳光照强度下表现出1.71 kg m-2 h-1的水蒸发速率以及94.1%的光蒸汽转换效率。在高浓度的模拟海水中，也表现出优异的耐盐性能，没有盐分的析出。基于上述一体化Janus 3DG材料具有优异的太阳能海水淡化和污水处理效果。