Hybrid nanofibrous aerogels for all-in-one solar-driven interfacial evaporation

Biomimic Design of Solar Steam Generation Devices Enabled by the Tannin-Iron Complex

Solar-powered steam generation equipment has experienced considerable advancement in recent years as it offers a cleaner and greener method for freshwater production. However, the devices always suffer from a complicated process, high cost, and salt accumulation, which hinder their further application. Here, inspired by the water lily, a highly efficient and antisalt accumulation interfacial solar-driven steam generation device was designed by using the tannic acid-Fe3+ complex as photothermal material. The designed evaporator could be quickly unfolded within 24 s after being irradiated with light and then produce fresh water. It folded within 10 s and then sank into water for removing the accumulated salt after removing the irradiation sources. In addition, the tannic acid-Fe3+ complex on the evaporator surface and the angle of the evaporator allowed light to be reflected several times within the evaporator, effectively increasing the solar energy conversion efficient (2.22 kg/(m2·h)), and apparently, the overall evaporation efficiency of 139.18% was achieved under 1 sun illumination. Moreover, it exhibited an extraordinary antisalt accumulation capacity (by working continuously for 7 days in 10 wt % saline water and 80% reduction in salt accumulation) as well as a low price ($ 1.11/m2). This design would provide a strategy to prepare an antisalt accumulation solar steam devices.

Fabrication of ATP/PEG/MnO2NWs composite for solar steam generation with high conversion efficiency

Solar steam generation is widely used in seawater desalination because of its high efficiency and environmental protection. However, using low-cost materials to produce efficient solar evaporators is a severe challenge. In this study, a porous carbon material was prepared by combining Attapulgite (ATP), Polyethylene glycol (PEG) and Manganese dioxide nanowires (MnO₂NWs) composite, through freeze-drying and high-temperature carbonization. The prepared CAPM aerogel shows a three-dimensional porous structure, which has high evaporation properties in pure water and simulated seawater. Under 1 sun simulated illumination, the pure water evaporation is 1.4574 kg m^-2h^-1 and the corresponding energy conversion efficiency is 85.94%. The prepared CAPM aerogel showed excellent durability and salt tolerance in 20%Nacl solution, indicating that the CAPM has excellent desalinization performance. In addition, CAPM aerogel has and exhibits super hydrophilic properties, which can transfer water molecules quickly. Due to the advantages of low cost, simple preparation method, and high solar energy conversion efficiency, the CAPM has excellent potential as a photothermal material for solar energy generation.

3D porous N-doped lignosulfonate/graphene oxide aerogel for efficient solar steam generation and desalination

Solar-driven interfacial evaporation has been considered one of the most promising approaches to tackle the issue of water scarcity. The salt resistance and water transport capacity of solar evaporation materials are essential to evaluate desalination performance. Herein, a 3D-porous N-doped lignosulfonate/graphene oxide (GO) aerogel (NLGA) was facilely prepared by a one-step hydrothermal method. By introducing ethylenediamine (EDA) as a nitrogen source, the wettability and water transport capacity of the aerogel were enhanced; by introducing lignosulfonate (LS), its porous structure was regulated, and its light absorption capability was significantly improved. The obtained aerogel exhibited an outstanding evaporation rate (1.57 kg m^-2 h^-1) and efficiency (95.2 %) under 1 sun illumination, which is significantly better than some reported foam-based solar evaporators. In addition, NLGA maintained a stable evaporation rate over long-term cyclic evaporation without visible salt accumulation on the surface. The good salt rejection performance is due to the rich-pore structure and superhydrophilicity of NGLA, which provides sufficient water supply to dissolve the salts during water evaporation. NLGA has enormous potential as a solar evaporator based on its excellent performance in solar vapor generation.