Achieving highly interfacial evaporation rate and continuous salt resistance simultaneously via multi-dimensional composite biomimetic evaporator
Lie Zou, He Zhang, Qianwang Chen, Size Zheng, Ning Chen, Xiaohu Wu, Xiaoke Li
Abstract
In response to the global freshwater crisis, various measures have been proposed. Solar-driven interfacial photoevaporation is gaining attention because its environmentally friendly and energy-efficient. However, challenges such as low solar-thermal conversion efficiency and low evaporation rates continue to hinder the advancement of solar photoevaporation technology. Inspired by Tamarisk, we proposed a multistage reflective structure using a hydrothermal method, increasing the carbon cloth (CC) surface area. Numerical simulations indicate that the plasmon resonance effect of the composites could effectively enhance the light absorption properties of the structures. Subsequently, a polyvinyl alcohol-phytic acid (PVA-PA) hydrogel was integrated with the composites to achieve effective separation of the evaporation layer from the water transport layer, thereby minimizing the interfacial light evaporation material. The PVA-PA/MnO 2 @CC evaporation system demonstrates excellent thermal management performance. Both experimental and simulation results confirm that the system can localize the heat obtained from photothermal conversion at the water–air interface. Additionally, the Marangoni effect, induced by the temperature gradient in the evaporation system, facilitates the transport of water in the PVA-PA hydrogel to the interface through microscopic holes. The evaporator exhibited an evaporation rate of 3.190 kg m -2 h −1 in deionized water, with an evaporation efficiency of 94.1 %. Even under high-concentration brine conditions, the evaporation rate remained high, and during continuous evaporation in high-concentration brine, the surface showed no significant salt accumulation. In summary, this work combines two-dimensional carbon cloth with three-dimensional hydrogel, and incorporates metal oxides onto the carbon cloth surface to further enhance its light-trapping ability. By synthesizing the advantages of both materials, the performance of the evaporator is significantly improved.