Cactus-inspired moisture harvesting for sustainable and efficient high salinity desalination

Abstract

Water scarcity has become a global issue that needs to be addressed urgently. Solar steam generation (SSG) is a promising technology to alleviate the water crisis through desalination and condensation. However, the stability and efficiency of SSG can be seriously impacted by salt accumulation after prolonged operation. Common salt rejection schemes are only applicable for low-salinity (<10 wt%) desalination. In this work, inspired by the cactus's fog-capturing feature, the atmospheric water harvesting (AWH) function is integrated by an interlocked braided fibrous framework (IBFF) to absorb moisture for sustainable salt dilution during high salinity (20 wt%) desalination. The loop-pile density/height of IBFF is regulated to mimic the cactus roots/spines with different architectures, thus optimizing the water absorption/moisture harvesting performance. The excellent moisture-induced salt dilution ability ensures efficient and sustainable high salinity desalination performance over cyclic operation, with an exceptional evaporation rate of up to 3.11 kg m−2·h−1 under 1 sun radiation. Overall, this new approach offers a practical possibility for durable and competitive high salinity desalination with a continuous water/moisture supply.