Solar interfacial evaporation properties of carbon nanotube polyvinyl alcohol composite surface

Solar interfacial evaporation significantly improves the efficiency of solar thermal evaporation. However, if the binding strength of the light-absorbing materials to the substrate material is not sufficient, it is easy to shed under the action of external forces in practical applications and reduce the solar-thermal conversion efficiency of the evaporation surface. To solve the problem, this paper proposes a composite surface by wrapping carbon nanotubes on the surface of the cellulose sponge skeleton using polyvinyl alcohol hydrogel. Carbon nanotubes have a good light absorptivity in the wavelength range of 250-2,500 nm. Moreover, the effects of carbon nanotubes concentration, polyvinyl alcohol concentration, and water supply path area on the evaporation performance are also optimized by experiments. The results show that the transparent polyvinyl alcohol not only enhances the binding strength of carbon nanotubes but also does not reduce the light absorptivity of the evaporation surface. Under the optimal ratio of the water supply path area of 20%, at a solar irradiation intensity of 1 kW center dot m-2, the evaporation rate of the evaporator reaches 1.345 +/- 0.034 kg center dot m- 2 center dot h-1 with an evaporation efficiency of 89.7% +/- 2.5%, evaporation performance with a long-term stability. This research provides a new method for the design and fabrication of evaporators for seawater desalination applications.