A loofah-based photothermal biomass material with high salt-resistance for efficient solar water evaporation

Clean water is the most basic resource for human use. Desalination, powered by solar energy to evaporate water, has arisen the wide attention compared with unsustainable and costly technologies. In this paper, a waste biomass derived evaporator composed of MXene nanosheets and loofah for high efficiency solar steam seawater desalination is proposed. After hydrophobic treatment, the upper loofah combined with MXene significantly improves the light absorption capacity. The bottom loofah, due to its natural superhydrophilicity and large holes and microchannels, not only ensures that sufficient water is pumped to the top layer for heating, but also prevents salt from accumulating on the evaporation interface. The evaporation rate of the multi-functional photothermal evaporator is up to 1.57 kg m−2 h−1, and the solar-thermal conversion efficiency is 95.5%. At the same time, the evaporator exhibits excellent self-desalination performance. In particular, the waste biomass derived evaporator based on loofah shows excellent stability and ensures its long-term performance in seawater desalination. This sustainable, cost-effective and environment-friendly photothermal composite is promising to achieve low-cost, large-scale waste water treatment and the production of clean water in water scarce areas.