Membrane-based air humidification-dehumidification desalination (MHDD) technology is an effective way to ease fresh water shortage owing to its excellent salt rejection. However, industrial applications pose higher requirements on membrane life expectancy. Membrane cleaning is considered as a potentially sustainable approach to prolong the operation time. Traditional cleaning methods are limited due to the poor recovery efficiency and the introduction of impurities. Here, a novel solar-assisted-self-healing N-doped MXene quantum dots (NMQDs)/ZnO-based membrane was fabricated to repair the water production capability of membranes contaminated by proteins from seawater. On the one hand, NMQDs with up-conversion properties absorb visible light and emit ultraviolet light, under which ZnO could be excited to form electron/hole pairs that help to degrade organic matter pollutants. On the other hand, the addition of NMQDs could improve the charge separation efficiency of ZnO. The synergistic effect of the two enhances the light absorption capacity of ZnO. The as-designed membrane exhibited excellent repair ability. The moisture permeation rate of the healed membrane reached 99.8% of the initial membrane after illumination. The self-healing membrane with solar energy is promising advances in sustainable desalination.
Keywords: MXene quantum dots; desalination; self-healing; solar energy; up-conversion.