Enhanced interfacial evaporation with wind-driven rotating sailboat-style evaporators

Interfacial evaporation powered by renewable energy provides a sustainable and environmentally friendly method of speeding up water evaporation for seawater desalination, or volume reduction of wet waste. This study develops an interfacial sailboat evaporator with a wind-driven rotatory motion to accelerate the evaporation rate (ER). Two distinct evaporator designs were fabricated: rectangular-shaped and leaf- shaped self-floating sailboats, each evaluated under wind speeds, from 0 to 3.8 m/s. Experimental results showed that the rotational evaporator led to microdroplet ejection from the sail surface, improving the evaporation performance at high wind velocities. Moreover, the leaf-shaped evaporator outperformed the rectangular one in stationary and rotatory modes, with efficient transport of water towards the center of the sailboat. Surface functionalization of both evaporators with reduced graphene oxide (rGO) further improved wind-driven interfacial evaporation, achieving rates of up to 8.13 kg/(m 2 ·h) in rotatory and 3.82 kg/(m 2 ·h) in stationary modes for water. The modified leaf-shaped evaporator also showed a higher ER for highly concentrated salt water, maintaining 6.25 kg/(m 2 ·h) and 3.22 kg/(m 2 ·h) in rotatory and stationary modes, respectively. These findings underline the potential of wind-driven rotating evaporators in enhancing evaporation for sustainable water treatment applications.