Simple mass transfer regulation achieves scaling-free zero liquid discharge of seawater desalination brine without chemical additive

Thermal-driven interfacial evaporation crystallization offers a promising path to zero liquid discharge (ZLD) for high-salinity brine. However, cocrystallization of specific minor salt species with major salts forms scaling that causes operational failure. Although chemical additives are commonly used to mitigate scaling, they pose potential environmental risks. This study presents a chemical-additive-free antiscaling strategy that suppresses unwanted cocrystallization by rationally enhancing the departure of scaling-causing species from the evaporation interface. As a proof of concept, a solar evaporator is designed to enhance the backflow of MgSO 4 , the primary scaling-causing species in seawater desalination brine, by precisely regulating its mass transfer distance. Under solar irradiation, the evaporator achieved a continuous evaporation of seawater desalination brine for over 408 hours with a stable evaporation rate of 4.29 kilograms per square meter per hour without any visible scaling, enabling uninterrupted ZLD operation. Outdoor field tests further validated the strategy’s practical applicability. This work offers transformative potential for achieving sustainable ZLD in brine management.