Date: 11-27-2018 - Tuesday - 08:00 PM - 10:00 PM
Zhiqiang Wang1 2 Ming Su1

1, Northeastern University, Boston, Massachusetts, United States
2, Tianjin Normal University, Tianjin, , China

Water evaporation with natural solar energy attracts much attention due to its wide applications as well as energy saving. However, this heating process is very slow under 1 sun shining. So current technology, which needs a large surface, collects the solar irradiation as much as possible, and concentrates the heat to accelerate this process. For future technology, evaporation upon local heating at air-water interface can be facilitated with energy saving, because such locally temperature gradient in the air-water system, compared to the heating scheme of bulk water, can effectively increase the heat utilization. Apparently, the implementation of such emerged photo thermal desalination technique is highly dependent on exploration of excellent photo thermal materials to absorb and evaporate water efficiently. In this work, we reported a low cost and high efficient evaporating material. Such an evaporating system achieved an extremely high water production rate of 1.34 kg h−1 m−2 and 89.9 % energy efficiency under 1 sun radiation. The excellent performance is attributed to the combination of multiple properties simultaneously exhibited by this as-prepared material, including its intrinsic blackbody-like high absorption, extremely low thermal loss to environment (low evaporating temperature and 1D water transporting), and automatic water transportation to the evaporating surface by capillary force through the huge microchannels. We also found the general relationships, not limited in our materials but all solar evaporation materials, between evaporating rate, energy efficiency and evaporating surface temperature. Following this relationship, people may control the steam temperature and the evaporating rate for some purpose, respectively.

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