Biomass-Derived Gradient and Aligned Structured Aerogel for Sustainable Agricultural Irrigation

Interface evaporation-driven hydroelectric systems integrating water purification and energy collection offer the potential for sustainable agricultural irrigation. However, achieving high evaporation rates and efficient energy harvesting poses challenges, particularly in optimizing evaporation and water transport. This study develops a gradient-aligned structured aerogel (GA aerogel), composed of biomass materials such as cellulose and chitosan, which utilizes efficient water transport through aligned cellulose channels, unique ion management in nanoscale channels, and chitosan's ability to reduce evaporation energy consumption, thereby enhancing water and energy harvesting performance. The GA aerogel achieves a solar absorption rate of 91.4%, an evaporation rate of 2.5 kg m^-2 h^-1, an output power of 680 nW cm^-2, and stable operation for over 120 h. Furthermore, by integrating a series array with capacitive energy storage, the system utilizes harvested electrical energy to irrigate plants with purified water, promoting sustainable agriculture and providing insights for designing biomass-based solar evaporators.