Bioinspired multi-scale core-spun yarn-based solar evaporator for ultra-efficient and durable high-salinity brine desalination

Abstract

Solar-driven interfacial desalination has been considered a promising and green technology for relieving worldwide water shortage because of its zero carbon emission. However, salt accumulation during evaporation results in a significant reduction in solar evaporation performance and sustained service life. High-performance and long-term salt-rejecting solar evaporators are urgently desirable. Inspired by the rapid water transfer driven by leaf transpiration and the capillary pressure in woody plants, we developed electrospun polyacrylonitrile (PAN) @carbon nanotubes (CNTs) nanofiber/cotton core-spun yarn (PCCS yarn) based solar evaporator enabled by the multi-branch microchannels and sub-microchannels for ultra-efficient and durable high-salinity brine desalination. The optimal PCCS yarn-based solar evaporator exhibits a record-high evaporation rate of 3.46 kg m−2h−1 under one sun illumination among 2D evaporators. Meanwhile, an excellent and stable brine desalination rate of ∼2.75 kg m−2h−1 for 100 h continuous solar irradiation is achieved even in 20wt% NaCl solution. The above results are attributed to the massive micro evaporation surfaces formed between nanofibers, rapid water replenishment in the radius direction, and orientational fast water transport by Laplace pressure along and across the PCCS yarn. In addition, the continuous preparation of the core-spun yarn by the conjugated electrospinning technology and the complete fabric production process in the textile industry make it possible for the practical application of the PCCS yarn-based solar evaporator. This work promotes the development of high-performance, long-term and scalable solar desalination devices.