A Self-Floating Balsa Wood Solar Evaporator: Simultaneously Achieving Seawater Desalination and Catalytic Degradation

Photothermal materials possess efficient light absorption and light-to-energy conversion capabilities, and have been widely applied in research on seawater desalination and sewage treatment. However, traditional solar desalination faces challenges such as poor salt resistance, low photothermal conversion efficiency, and the inability to effectively remove wastewater discharged from seawater. In this study, we designed a self-floating solar evaporator with a vertically arranged and porous structure. By employing a simple "impregnation-crosslinking-reduction" method, we induced cross-linking in balsa wood/MXene/MnO₂ (MMW). Among them, MXene exhibits exceptionally Superior efficiency in photothermal energy conversion and is widely applied as a photothermal material in the field of seawater desalination. Meanwhile, MnO₂ nanoflowers, rich in oxygen vacancies, can effectively activate peroxydisulfate (PDS), demonstrating efficient catalytic performance. Within the evaporator, they spontaneously establish a wet, porous internal structure and specialized water pathways. Under such conditions, The system demonstrates a maximum evaporation capacity of 1.90 kg m⁻² h⁻¹, along with an evaporation efficiency of 113.4%. Moreover, the evaporator demonstrates high degradation rates(94.09% for 50 mg L⁻¹ methylene blue and 95.31% for 100 mg L⁻¹ Rhodamine 6G). In addition, this evaporator enables salt to be expelled from its interior to the surface via convection,which can acquire freshwater efficiently and sustainably. Furthermore, we used the purified water collected from evaporation to irrigate mung beans, which were able to germinate and grow normally. This work provides a direction for the application of evaporators and offers an alternative approach to addressing water scarcity and enhancing water utilization.