Publication: Copper oxide nanocrystals based electrospun nanofibrous membrane for solar water evaporation
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Date
2024-03-01
Authors
Zhao, Jianghu
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Abstract
Solar water evaporation has attracted widespread research, which narrowed the huge gap between inadequate clean water supply and human needs. For membrane evaporators, improving the solar absorption, water supply ability, and thermal management are critical to photothermal performance. Developing a suitable structure of light absorbing material could be a feasible approach to address these problems and to enhance evaporation performance. Yet there is limited research focus on this topic. In this study, three different structural CuO-based membrane evaporators were developed to adjust the membrane properties for improving solar evaporation performance. First of all, a triple-layer P/CuO-nanocluster nanofibrous membrane was fabricated through electrospinning, heating and hydrothermal processes. The top and bottom hydrophilic layers of CuO-nanocluster can effectively absorb sunlight, transport water, and suppress salt accumulation on the membrane surface. The middle layer of nanofibrous PVDF-HFP thin-film can support the whole system. The resultant membrane showed an evaporation rate of 1.21 kgm−2h−1 and efficiency of 83.57% for 3.5 wt.% saline water, which is higher than control group without membrane of 0.24 kgm−2h−1 and 16.26%, respectively. The next membrane structure design was core-shell structural P/CuO-Ag NPs nanofibrous membrane. During the electrospinning process, hydrophilic PVP was introduced to help more CuO growth media penetrating into the membrane interior during hydrothermal process. The Ag NPs incorporation enhanced membrane light absorption and wettability. The resultant core-shell P/CuO-Ag membrane achieved better evaporation rates of 1.31 kgm−2h−1 and efficiency of 90.77% for 3.5 wt.% saline water. The final membrane structure was hollow structural P/CuO-C nanofibrous membrane synthesized through coaxial electrospinning. During the fabrication process, the spinning precursor mixed with C NPs in the shell layer to enhance the light absorption while the hydrophilic PVP in the core layer was removed in the hydrothermal step to form a hollow structure. The formation of the hollow structure not only enhanced light absorption but also improved thermal management capacity of the membrane. As a result, the hollow structural P/CuO-C membrane achieved the best evaporation rate of 1.36 kgm−2h−1 and efficiency of 93.07% for 3.5 wt.% saline water as compared to the previous two structures. The outcome of this work will inspire subsequent research to construct of suitable architecture materials for potential applications in water treatment, thermal insulation, energy generation, energy storage, and other related fields.