Sandwich-structured MXene/wood aerogel with waste heat utilization for continuous desalination

Solar-driven interfacial evaporation technology has shown promising prospect in desalination. However, the weakened energy efficiency caused by intermittent solar irradiation and salt deposition during continuous desalination process is the great obstacle in the application. Here, we report a sandwich-structured MXene/wood aerogel coupled with phase change materials (PCMs) evaporator for high-efficiency and continuous desalination. The multi-stage water transport channel of DWA and the enhanced thermal localization effect of MXene and DWA optimize the performance of the evaporator. The PCMs block as a waste heat recovery module largely reduces heat loss. Under one solar irradiation, the evaporation rate of 2.0 kg·m−2·h−1 and energy efficiency of 92.6 % are achieved. The production of fresh water can reach 15 kg·m−2·day−1. The evaporation rate under intermittent solar irradiation can also reach 1.77 kg·m−2·h−1. There is no clear decrease in evaporation performance as well as salt accumulation for 5 days of continuous evaporation. The energy balance, water transport, thermal localization and salt resistance mechanisms of solar-driven interfacial evaporation are analyzed. This work shows an excellent way to break the limitations of conventional solar interfacial evaporation and achieve stable desalination under intermittent solar irradiation.