A novel floatable composite hydrogel for solar evaporation enhancement

Abstract

Solar evaporation is an economically feasible method for desalination and distillation. Herein, we report a facile method to synthesize a floatable composite hydrogel with squid ink nanoparticles, silica aerogel, poly(vinyl alcohol) and acrylamide. Squid ink nanoparticles have good photothermal conversion efficiency. The silica aerogel can effectively reduce the density of the hydrogel and allow the composite hydrogel to float on the water surface. The good hydrophilicity of the hydrogel facilitates the transport of water molecules from the bottom to the top of the floatable composite hydrogel. In the evaporation process, these properties enable the floatable composite hydrogel to centrally heat the surface of the water, thus improving the water evaporation efficiency. The results of the evaporation experiments showed that the seawater evaporation rate of the floatable composite hydrogel was 4.73 times higher than that of the traditional process. Furthermore, the good mechanical strength and flexibility of the hydrogel provide a guarantee for its recovery and reuse in practical applications. This low-consumption, easy-to-manufacture and durable floatable composite hydrogel provides a new way for solar desalination.