Storer Daniel Peter, Phelps Jack Leslie, Wu Xuan, Owens Gary, Khan Nasreen Islam, Xu Haolan
Future Industries Institute, University of South Australia, Mawson Lakes Campus, Adelaide SA 5095, Australia.
Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom.
ACS Appl Mater Interfaces. 2020 Apr 1;12(13):15279-15287. doi: 10.1021/acsami.0c01707. Epub 2020 Mar 18.
Solar-steam generation is one of the most promising technologies to mitigate the issue of clean water shortage using sustainable solar energy. Photothermal aerogels, especially the three-dimensional (3D) graphene-based aerogels, have shown unique merits for solar-steam generation, such as lightweight, high flexibility, and superior evaporation rate and energy efficiency. However, 3D aerogels require much more raw materials of graphene, which limits their large-scale applications. In this study, 3D photothermal aerogels composed of reduced graphene oxide (RGO) nanosheets, rice-straw-derived cellulose fibers, and sodium alginate (SA) are prepared for solar-steam generation. The use of rice straw fibers as skeletal support significantly reduces the need for the more expensive RGO by 43.5%, turning the rice straw biomass waste into value-added materials. The integration of rice straw fibers and RGO significantly enhances the flexibility and mechanical stability of the obtained photothermal RGO-SA-cellulose aerogel. The photothermal aerogel shows a strong broad-band light absorption of 96-97%. During solar-steam generation, the 3D photothermal aerogel effectively decreases the radiation and convection energy loss while enhancing energy harvesting from the environment, leading to an extremely high evaporation rate of 2.25 kg m h, corresponding to an energy conversion efficiency of 88.9% under 1.0 sun irradiation. The salinity of clean water collected during the evaporation of real seawater is only 0.37 ppm. The materials are environmentally friendly and cost-effective, showing great potential for real-world desalination applications.
太阳能蒸汽产生是利用可持续太阳能缓解清洁水短缺问题最具前景的技术之一。光热气凝胶，尤其是三维（3D）石墨烯基气凝胶，在太阳能蒸汽产生方面展现出独特优势，如重量轻、柔韧性高、蒸发速率和能量效率优异。然而，3D气凝胶需要更多的石墨烯原材料，这限制了它们的大规模应用。在本研究中，制备了由还原氧化石墨烯（RGO）纳米片、稻草衍生的纤维素纤维和海藻酸钠（SA）组成的3D光热气凝胶用于太阳能蒸汽产生。使用稻草纤维作为骨架支撑显著减少了对更昂贵的RGO的需求，减少了43.5%，将稻草生物质废料转化为增值材料。稻草纤维与RGO的结合显著提高了所得光热RGO-SA-纤维素气凝胶的柔韧性和机械稳定性。该光热气凝胶显示出96-97%的强宽带光吸收。在太阳能蒸汽产生过程中，3D光热气凝胶有效降低了辐射和对流能量损失，同时增强了从环境中获取能量的能力，导致极高的蒸发速率为2.25 kg m h，在1.0个太阳辐照下对应的能量转换效率为88.9%。在实际海水蒸发过程中收集的清洁水盐度仅为0.37 ppm。这些材料环保且具有成本效益，在实际海水淡化应用中显示出巨大潜力。
