Self-contained Janus Aerogel with Antifouling and Salt-Rejecting Properties for Stable Solar Evaporation
Self-contained Janus Aerogel with Antifouling and Salt-Rejecting Properties for Stable Solar Evaporation
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独立的 Janus 气凝胶具有防污和防盐性能，可实现稳定的太阳能蒸发
DOI：
10.1021/acsami.1c02198
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发表时间：
2021
影响因子：
9.5
通讯作者：
Chen Su
中科院分区：
文献类型：
--
作者：
Liu Zhiwu;Qing Ren-Kun;Xie An-Quan;Liu Hao;Zhu Liangliang;Chen Su
通过将太阳能吸收器从大量工作流体分离的Janus结构界面蒸发由于其低热损失和高太阳能转换效率而引起了极大的关注，用于脱盐、水净化、能量产生等。然而，具有不连续界面过渡和低效光热材料的完全分离的双层结构破坏了其长期使用和大规模实际开发。本文中，具有连续对齐的贯穿微通道的低成本Janus单片壳聚糖气凝胶已被证明对海水淡化和废水净化具有高效的光热效应。顶部太阳能吸收层通过入射光在对准的微通道中的多次内反射来增强宽带光吸收和光热转换效率。此外，绝缘/亲水底层促进水输送和热局部化，同时防止盐/污垢积聚。结果表明，在1个太阳照射下，长期太阳能蒸发率为1.76 kg m-2 h-1，对应的光-蒸汽效率为1.91%。值得注意的是，贯穿气凝胶的大容器微通道和有利的溶胀性质提供了足够的水补充和储存，用于完全隔离自给式蒸发，说明了增强的和时间延长的自给式太阳能蒸汽产生。这种低成本的双层气凝胶在各种流体中具有显着的循环稳定性，为偏远农村地区的淡水生产提供了潜在的机会。
Janus structural interfacial vaporization by separating the solar absorber from the bulk working fluid has attracted tremendous attention due to its low heat losses and high solar conversion efficiency for desalination, water purification, energy generation, etc. However, a totally separated double-deck structure with a discontinuous interfacial transition and inefficient photothermic materials undermines its long-term use and large-scale practical exploitation. Herein, a low-cost Janus monolithic chitosan aerogel with continuous aligned run-through microchannels has been demonstrated to have a highly efficient photothermic effect on seawater desalination and wastewater purification. The top solar absorber layer enhances broadband light absorption and photothermal conversion efficiency via the multiple internal reflection of incident light in the aligned microchannels. Moreover, the insulating/hydrophilic bottom layer promotes water transportation and heat localization, and simultaneously prevents salt/fouling accumulation. As a result, a long-term solar vaporization rate of ∼1.76 kg m–2h–1is achieved, corresponding to a light-to-vapor efficiency of ∼91% under 1 sun irradiation. Notably, the large-vessel microchannels throughout the aerogel and favorable swelling property provide sufficient water replenishment and storage for completely isolating self-contained evaporation, illustrating an enhanced and time-extended self-contained solar steam generation. Such a low-cost bilayer aerogel with remarkable cycling stability in various fluids offers potential opportunities for freshwater production in remote rural areas.