Bionic solar driven interface evaporation aerogels inspired by mushroom surface textures with high salt collection and desalination capacity

Abstract

Driven by its low cost, high sustainability, and simple construction, Solar-driven interfacial evaporation technology is coming to the fore as a hopeful solution and is garnering significant research interest. When dealing with salt solutions, as the solution on the interface continues to evaporate, the salt in the solution will accumulate at the evaporation interface, hindering the absorption of light and the release of vapor. In order to get good salt collection and desalination capacity on the surface, stripes structures are designed to regulate and collect salt crystallization. In this work, the bionic aerogel with mushroom surface stripes was created utilizing a 3D template approach with carboxylated multi-walled carbon nanotubes (MWCNTs-COOH), polyvinyl alcohol (PVA), and sodium alginate (SA). The stripes not only effectively expanded the evaporation area, thus improving the light absorption capacity, but also adjusted the salt crystallization performance. The fabricated bio-inspired aerogel combines excellent light absorption and mechanical strength, resulting in an excellent evaporation rate of 1.64 kg m −2 h −1 under diverse solar intensities. This performance is further underscored by its 84.18 % solar energy utilization rate under standard solar irradiation. We conducted desalination experiments using real seawater, and the salt collection rate reached 0.089 kg m −2 h −1 . In a variety of wastewater purification experiments, the bionic gas gel has excellent purification effect. When processing saltwater, the salt crystallizes first on the surface stripes due to the Marangoni effect caused by the stripe structure, keeping the middle area of the photothermal layer clean. This is an ideal choice for treating various types of salt-containing wastewater and achieving desalination performance.

Topics & Concepts