ABSTRACT
Atmospheric water harvesting (AWH) technology is a new strategy for alleviating freshwater scarcity. Adsorbent materials with high hygroscopicity and high photothermal conversion efficiency are the key to AWH technology. Hence, in this study, a simple and large-scale preparation for a hygroscopic compound of polyurethane (PU) sponge-grafted calcium alginate (CA) with carbon ink (SCAC) was developed. The PU sponge in the SCAC aerogel acts as a substrate, CA as a moisture adsorber, and carbon ink as a light adsorber. The SCAC aerogel exhibits excellent water absorption of 0.555-1.40 g·g-1 within a wide range of relative humidity (40-80%) at 25 °C. The SCAC aerogel could release adsorbed water driven by solar energy, and more than 92.17% of the adsorbed water could be rapidly released over a wide solar intensity range of 1.0-2.0 sun. In an outdoor experiment, 57.517 g of SCAC was able to collect 32.8 g of clean water in 6 h, and the water quality meets the drinking water standards set by the World Health Organization. This study suggests a new approach to design promising AWH materials and infers the potential practical application of SCAC aerogel-based adsorbents.
ABSTRACT
Invited for this month's cover, the researchers from Huaqiao University and Jilin Jianzhu University. The Cover image shows the use of spent graphite to prepare hydrogels for photothermal evaporation to produce clean water. The Research Article itself is available at 10.1002/cssc.202300845.
ABSTRACT
Solar-driven interfacial evaporation technology is regarded as an attracting sustainable strategy for obtaining portable water from seawater and wastewater, and the recycle of waste materials to fabricate efficient photothermal materials as evaporator to efficiently utilize solar energy is very critical, but still difficult. To this purpose, graphite recovered from spent lithium-ion batteries (SLIBs) was realized using a simple acid leaching method, and a reconstructed graphite-based porous hydrogel (RG-PH) was subsequently fabricated by crosslinking foaming method. The incorporation of reconstructed graphite (RG) improves the mechanical characteristics of hydrogels and the light absorption performance significantly. The evaporation rate of optimized RG-PH can constantly reach 3.4278â kg m-2 h-1 for desalination under a one solar irradiation, and it also showed the excellent salt resistance in various salty water. Moreover, RG-PH has a strong elimination of a variety of organic contaminants in wastewater, including the typical volatile organic compound of phenol. This research shows the potential application of flexible and durable solar evaporators made from waste materials in purifying seawater and wastewater, not only contributing to carbon neutrality by recycling graphite from SLIBs, but also ensuring the cost-effectiveness harvest of solar energy for constantly obtaining clean water.