Multi-Functional Janus Hollow Solar Evaporator Based on Copper Foam for Non-Contact High-Efficiency Solar Interfacial Distillation

Asa sustainable, clean, and friendly technology with a minimalcarbon footprint when treating seawater or wastewater, interfacialsolar vapor generation (ISVG) technology is a great alternative totraditional desalination and water purification methods (e.g., reverseosmosis and ultrafiltration). So far, it presents tremendous potentialfor applications in realizing desalination of seawater or brine, wastewatertreatment, and so forth. However, the precipitated salt particlesduring conventional ISVG inevitably block the evaporator surface,resulting in the degradation of photothermal conversion and decreaseof evaporation rate. Herein, a multi-functional non-contact Janushollow evaporator based on copper foam was prepared, which was assembledby a hydrophobic light-to-heat conversion layer and a hydrophilicinterfacial water evaporation layer as two separate parts. Accordingly,the precipitated salt in the ISVG system does not block the photothermalinterface, increasing the stability of solar capture and reusabilityof the evaporator. Notably, the hollow structure of the evaporatorhas a local interfacial heating effect, endowing the evaporation systemwith a high seawater evaporation rate of 2.249 kg m(-2) h(-1). The evaporator is capable of stable operationfor 10 h under 1 sun illumination even when evaporating concentratedbrine (15 wt %). Moreover, the evaporation rate of water under onesun irradiation reached 2.284 kg m(-2) h(-1) and the solar-to-vapor efficiency reached 96.6%. Not only that,the evaporator was able to successfully purify wastewater containingdyes and heavy metal ions. The multi-functional Janus hollow interfacialsolar evaporator will provide inspiration for upcoming research onthe production of safety water.