Inspired by Turtle: 3d Raised Knitted Solar Evaporator Achieves Efficient Seawater Desalination

Abstract

The efficient solar interface evaporation technology offers a solution to the scarcity of freshwater resources on Earth. At present, the efficient and cost-effective large-scale fabrication of devices exhibiting high-performance photothermal conversion and evaporation properties remains a key area of research. Our inspiration from turtles, coupled with traditional knitting techniques, led to the innovative design and production of a three-dimensional (3D) raised fabric utilizing heat-shrink properties of yarn. By integrating polydopamine (PDA) and carbon black (CB)/polyvinyl alcohol (PVA), we created a 3D fabric-base solar evaporator. Due to the periodic structural design and the synergistic effects of micro/nano-materials, this evaporator achieves a peak solar absorptance of 99.6%, with surface temperatures reaching 152.9 °C in dry and 70 °C in wet conditions under 3 sun. It demonstrates an evaporation rate of 1.57 kg m-2 h-1 and an evaporation efficiency of 92.89% under 1 sun. The evaporator demonstrates remarkable hydrophilicity, ensuring a sufficient water supply without any salt accumulation over extended periods of use, facilitating continuous water evaporation. It exhibits potential for applications in seawater desalination, heavy metal ion removal and organic dye elimination. Hence, bio-inspired solar evaporators present an effective strategy for sustainable seawater desalination.

Keywords: biomimicry, Solar evaporator, 3D raised fabric, knitting technology, seawater desalination