Marine biomass-derived composite aerogels for efficient and durable solar-driven interfacial evaporation and desalination

Solar-driven interfacial evaporation is an emerging and sustainable technology with growing potential for applications in water distillation and desalination. Despite the ongoing progress in clean water production, the high cost, delicate structures, leaching and disposal of synthetic materials remain the major roadblocks toward large-scale and real-world applications. Herein, nanocellulose (NC) is successfully extracted from abundant, inexhaustible and biodegradable biomass Ulva (Enteromorpha) prolifera that collected from the coast of Qingdao, China. Incorporation of polyvinyl alcohol (PVA) into the NC scaffolds and subsequent cross-linking endow the composite aerogels with efficient water diffusion, enhanced mechanical strength and good deformation resistance. The cross-linked composite aerogels can serve as main structural elements and integrate a monolithic, self-floating and durable steam generator. Under one sun, the good water evaporation rate of 1.4 kg m⁻² h⁻¹ is among the best-performing interfacial steam generators constructed by using cellulose-based materials as structural components. This study demonstrates a new concept of using marine (blue) biomass-derived NC as crude material and building block to construct high-performance and durable interfacial steam generators, synergistically considering clean water production and sustainability of marine ecosystems.