Recyclable Polydopamine-Functionalized Sponge for High-Efficiency Clean Water Generation with Dual-Purpose Solar Evaporation and Contaminant Adsorption

Solar desalination of seawater is an attractive and environmentally friendly method to solve the long-standing water crisis. However, its efficiency is highly reliant on solar intensity. Additionally, increasing contamination in water makes it difficult to generate clean water through the solo desalination process. To address this, we propose a polydopamine (PDA)-functionalized hybrid material with dual-purpose solar evaporation and contaminant adsorption for highly efficient clean water production in all-weather conditions. The hybrid material is fabricated by polymerization of dopamine onto a commercial sponge in a facile, low-cost, and scalable manner. With excellent light absorption and chelation capabilities, the PDA film coated on sponge acts as both a photothermal material and adsorbent that allow us to achieve clean water production with solar desalination when sunshine and with contaminant adsorption when cloudy or at night. Meanwhile, the solar evaporation and contaminant adsorption of the PDA-sponge are synergized with one another, resulting in the PDA-sponge that is a desirable material with the capability of continuous clean water production in all-weather conditions. The PDA-sponge is also highly recyclable with a high retention rate of evaporation and adsorption efficiency even after 10 cycles. The promising PDA-based hybrid is believed to inspire new strategies for superior water treatment materials.