Carbonized potato lamella-based hydrogel composite for efficient solar-driven interfacial evaporation with high salt-resistance

Solar-driven interfacial evaporation has great potential for seawater and wastewater purification treatment due to its high evaporation efficiency and environmental friendliness. However, salt deposition may occur during the actual desalination process, which can affect the performance and lifespan of the evaporator. In this study, a hydrogel (H) evaporator based on biomass material was developed, which encapsulated carbonized potato (CP) lamella into the sodium alginate (SA) framework (abbreviated as SA-H@CP). Due to the excellent solar energy collection ability of two-dimensional carbonized potato lamella, combined with the strong water transport capability of the hydrogel, the evaporator exhibited efficient photothermal conversion ability and super hydrophilic properties that resulted in excellent salt resistance. The SA-H@CP evaporator can achieve an evaporation rate of 1.36 kg m−2 h−1, and an efficiency of 85 % in pure water under 1 sun illumination. The concentration of salt ions in the produced freshwater was much lower than the drinking water standard set by the World Health Organization (WHO). This work provides a solution for the large-scale promotion of solar-driven interfacial evaporation technology for seawater desalination.