Mechanically robust composite hydrogels for high performance solar driven interface evaporation

Three dimensional composite hydrogels have been good candidates for solar driven interfacial evapora-tion, and it has remained a great challenge to develop high performance hydrogel evaporators with excel-lent mechanical properties, high evaporation efficiency and rate, and outstanding durability. Here, we prepare a polyvinyl alcohol (PVA)/acidified carbon nanotubes (ACNTs) composite hydrogel for solar -powered desalination. ACNTs are uniformly dispersed in the hydrogel and forms hydrogel bonding with PVA macromolecules, greatly improving the mechanical properties of the polymer hydrogel. With excel-lent light absorption, heat localization and water transport capabilities, the composite hydrogel evapora-tor possesses a high evaporation rate (up to 3.85 kg.m(-2).h(-1)) and a photothermal conversion efficiency of 87.6%. This hydrogel evaporator can work in a high concentration brine and during cyclic evaporation, exhibiting outstanding salt rejection performance and long-term durability. The high performance ACNTs filled hydrogel shows promising applications in solar desalination. (c) 2022 Elsevier Ltd. All rights reserved.