Three-dimensional macroporous foamy MXene membrane with high efficiency on interfacial evaporation and wastewater purification

Abstract

With the advantages of abundant surface hydrophilic groups and high photothermal conversion efficiency, MXene has attracted much attention in the field of photothermal evaporation for water production, but the drawback of easy accumulation limits its application in solar energy-driven interfacial evaporation. In this work, we present the process of creating three-dimensional macroporous foamy MXene membranes (FMXM) using Ti3C2 MXenes through the sacrificial use of melamine formaldehyde spheres (MFs) templates. In contrast to MXene membrane (MXM) evaporators, FMXM-based evaporators demonstrate exceptional light-to-heat conversion efficiency. The loosely porous structure of the FMXM facilitates a pathway for water transport, while the pleated surface minimizes light reflection. These factors contribute to the high light absorption capability and efficient water transfer rate of the FMXM evaporator. The evaporation rate and evaporation efficiency were 1.54 kg m−2 h−1 and 87.1 %, respectively, at one solar lower radiation intensity. In addition, FMXM exhibits commendable evaporation rates and evaporation efficiencies across various salt solutions, including highly saline brines, which have significant potential for application in solar-assisted desalination processes. The effectiveness of wastewater treatment was assessed, revealing the complete removal of dye contaminants. Our results break through the limitations of MXene material stacking, provide a scalable strategy, and demonstrate its potential in solar driven interfacial evaporation.