Synergy design and performance optimization of hydrogel-based materials for solar driven water purification applications

Abstract

Advanced water purification technologies that are efficient, convenient, and low-energy are highly sought after in both scientific and industrial sectors, particularly in regions facing acute water shortages. Interface solar vapor generation (ISVG) presents a promising solution due to its high solar-to-water conversion efficiency, zero-energy cost, portability, and environmental friendliness. Hydrogel-based evaporation platforms, with their unique interconnected network structures, high hydrophilicity, and controllable photothermal hybrid properties, are considered leading candidates in this field. They offer balanced tuning between continuous water supply and minimal heat loss, salt resistance, and low enthalpy change. In this work, we explore the relationship between various hydrogel preparation methods and their performance, emphasizing the importance of selecting appropriate hydrogel precursors and optimizing cross-linking strategies to tailor material properties. Additionally, this review highlights recent advancements in hydrogel-based ISVG systems, focusing on system optimization factors such as photothermal management, water transportation, enthalpy of evaporation, and salt resistance. Furthermore, precise equipment designs, including composite hydrogel-based evaporators, multilevel structured hydrogel evaporators, 3D printed evaporators, Janus structures, and membrane evaporators, are crucial for enabling rapid condensation and water collection, adapting to diverse operational conditions, and achieving scalability for industrial production. We also highlight key opportunities and challenges in this domain. Hydrogel-based evaporation platforms have extensive applications in water purification, electricity generation, and atmospheric water harvesting, but there remains substantial potential for further innovation, such as developing materials with improved mechanical properties, enhancing synergies in evaporation systems, and reducing heat loss. Hydrogel-based evaporation platforms are poised to offer forward-looking multifunctionality, smart responsiveness, and scalability for potential industrial implementation.