Upcycling Tonne-Scale Furniture into 3D Solar Steam Generators for Water Harvesting and Carbon Mitigation

To address the intersecting challenges of solid waste, carbon emissions, and freshwater scarcity, this study presents a scalable methodology to upcycle discarded wooden furniture into high-performance 3D interfacial solar steam generators (ISSGs) via high-temperature gasification. Key findings demonstrate that the resulting biochar (BC-200) features a hierarchical porous structure, an expanded surface area (106.0 m² g-1), and ~90% broadband optical absorption. By integrating this biochar into a 0.5 cm-thick 3D cubic absorber with a balanced capillary wicking system, the device achieved an exceptional evaporation rate of ~1.9 kg m−2 h−1 and 127% solar-to-vapor efficiency under 1-sun irradiation, alongside a robust outdoor water yield of 12.59 kg m−2 day−1. Ultimately, this upcycling approach delivers a threefold climate mitigation impact—avoiding landfill emissions, directly sequestering carbon, and indirectly averting greenhouse gases—offering a practical pathway toward global carbon neutrality and decentralized water purification.