Self-floating chitosan/polyvinyl alcohol/genipin aerogel for durable solar-driven desalination and wastewater purification

Conventional solar evaporators often suffer from salt accumulation, biofouling, and structural instability, limiting their practical use in sustainable freshwater production. Herein, a lightweight, self-floating chitosan/polyvinyl alcohol/genipin aerogel (CPG) was developed through an eco-friendly, photosensitizer-free crosslinking and aerogelation strategy for solar-driven desalination and wastewater purification. The optimized CPG aerogel combines broadband optical absorption of 97 %, robust mechanical stability, and an interconnected macroporous network, enabling rapid water replenishment, vapor transport, and salt rejection. Under 1 sun irradiation, CPG achieved a high evaporation rate of 3.85 kg·m −2 ·h −1 and maintained stable performance in hypersaline brine containing 25 wt% NaCl. During real seawater desalination, the evaporation–condensation process effectively rejected non-volatile ions, producing purified water that met WHO drinking water standards. CPG also generated dye-free condensates from dye-containing wastewater through distillation separation and interfacial retention, rather than direct dye degradation. In addition, the aerogel exhibited stable evaporation performance across pH 2–12 and light-enhanced antibacterial activity with > 99.9 % bacterial inactivation. This integrated self-floating aerogel design provides a promising platform for durable solar desalination and wastewater purification.