Zhang Shaochun, Zang Linlin, Dou Tianwei, Zou Jinlong, Zhang Yanhong, Sun Liguo
School of Chemical Engineering and Materials, Heilongjiang University, Harbin 150080, P. R. China.
State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, P. R. China.
ACS Omega. 2020 Feb 5;5(6):2878-2885. doi: 10.1021/acsomega.9b03718. eCollection 2020 Feb 18.
Biomass wastes are abundant and common in our daily life, and they are cost-effective, promising, and renewable. Herein, collected willow catkins were used to prepare a hydrophilic biochar composite membrane, which was placed in a tree-like evaporation configuration to simulate a natural transpiration process. The strong light absorption (∼96%) of the biochar layer could harvest light and convert it into thermal energy, which then is used to heat the surrounding water pumped by a porous water channel via capillary action. A hydrophilic light-absorber layer remarkably increased the attachment sites of water molecules, thereby maximizing the use of thermal energy. At the same time, hierarchically porous structure and large specific surface area (∼1380 m g) supplied more available channels for rapid water vapor diffusion. The as-prepared composite membrane with a low-cost advantage realized a high evaporation rate (1.65 kg m h) only under 1 sun illumination (1 kW m), which was improved by roughly 27% in comparison with the unmodified hydrophobic composite membrane. The tree-like evaporation configuration with excellent heat localization resulted in the evaporator achieving a high solar-to-vapor conversion efficiency of ∼90.5%. Besides, the composite membrane could remove 99.9% sodium ions from actual seawater and 99.5% heavy metal ions from simulated wastewater, and the long-term stable evaporation performance proved its potential in actual solar desalination. This work not only fabricated an efficient evaporator but also provided a strategy for reusing various natural wastes for water purification.
生物质废弃物在我们的日常生活中丰富且常见，它们具有成本效益、前景广阔且可再生。在此，收集的柳絮被用于制备一种亲水性生物炭复合膜，该复合膜被置于树状蒸发结构中以模拟自然蒸腾过程。生物炭层的强光吸收能力（约96%）能够收集光线并将其转化为热能，然后通过毛细作用用于加热由多孔水通道泵送的周围水体。亲水性光吸收层显著增加了水分子的附着位点，从而使热能得到最大化利用。同时，分级多孔结构和大比表面积（约1380 m²/g）为快速的水蒸气扩散提供了更多可用通道。所制备的具有低成本优势的复合膜仅在1个太阳光照强度（1 kW/m²）下就实现了高蒸发速率（1.65 kg/(m²·h)），与未改性的疏水复合膜相比提高了约27%。具有出色热局域性的树状蒸发结构使蒸发器实现了约90.5%的高太阳能-蒸汽转换效率。此外，该复合膜能够从实际海水中去除99.9%的钠离子以及从模拟废水中去除99.5%的重金属离子，其长期稳定的蒸发性能证明了其在实际太阳能海水淡化中的潜力。这项工作不仅制造了一种高效蒸发器，还为将各种天然废弃物再利用于水净化提供了一种策略。
