Solar Driven Interfacial Steam Generation Derived from Biodegradable Luffa Sponge

A chemically treated luffa sponge (LS) derived from the ripe fruit of the Luffa cylindrica (LC) plant is investigated as an efficient solar photothermal conversion material for water purification applications for the very first time. Hydrophilicity and solar absorbance of the LS are enhanced by dopamine treatment and candle soot surface coating. The fabricated surface modified LS (SM-LS) leads to a superb solar evaporation rate of water as high as 1.30 kg m⁻² h⁻¹, which is five times higher than that of the freshwater under 1 sun illumination. The outdoor experiment shows an excellent solar evaporation efficiency of 79.98%, which is significantly higher than other low-cost materials. Such SM-LS can be further applied to desalinate seawater, where it is shown that 1 m² of surface-modified LS can produce 7.5–8 L of freshwater per day. Hence, the proposed system can be utilized in remote areas and refugee camps.