Design of a bio-inspired nanofiltration channel for self-driven desalination and cleansing

Abstract

Efficient and energy-saving water filtration approach is the most essential issue in desalination. This study introduces a design of bio-inspired nanofiltration channel, which realizes spontaneous droplet self-driving and water-ion separation. The droplet is injected from a wedge-shaped channel into a nano-restrained channel. The separation of ions and water can be achieved by adjusting the layer spacing of the confined interlayer channel, which makes this bio-inspired nanochannel hold considerable promise for desalination. Notably, the wettability of the channel can be translated from hydrophobic to hydrophilic which induces reverse droplet motion, facilitating self-cleansing of the channel. This spontaneous injection process is attributed to van der Waals forces at the molecular scale, which provides the driving force and the separation pressure. The geometric parameters of nanofiltration channel effects on droplet transport are explored. The findings suggest that a smaller opening angle of the wedge-shaped channel and a wider nano-restrained channel significantly enhances the injection process. Our findings provide a novel perspective to the design of next-generation desalination devices, with potential implications for enhancing both their performance and efficiency.