Enhancing solar evaporator efficiency and reducing salt fouling by separating evaporation surface and water pump

Solar-driven evaporation has emerged as a promising approach for sustainable seawater purification. However, most reported methods often suffer from problems such as low efficiency, scaling, and fouling. To address these long-term limitations, this study presents a novel solar evaporator design that separates the evaporation surface from the water pumping column. This design allows the water pumping column to maintain the same salinity and temperature as the bulk seawater, minimizing scaling, fouling and heat loss. The system employs a temperature-responsive hydrogel with aligned pores to facilitate non-powered water transport driven by diurnal temperature fluctuations. Additionally, the design uses a floating graphene composite paper (GCP) evaporation surface that moves with the water level inside the evaporation chamber, automatically adjusting the angle between the evaporation surface and the sun to optimize energy absorption. Experimental results demonstrate that this configuration effectively prevents salt accumulation within the water channels, minimizes heat loss, and achieves enhanced evaporation rates, thereby offering a viable solution for efficient and sustainable seawater purification. An innovative design that physically decouples the solar evaporation surface from the bulk water transport pathway. This separation effectively mitigates salt accumulation on the evaporation surface and reduces thermal energy losses, addressing key limitations of conventional solar evaporation systems. • A solar evaporator with a separate evaporation surface and water pump is designed. • A temperature-responsive hydrogel is used to operate the water pump. • The angle between the evaporation surface and the horizon changes automatically. • No salt fouling was observed in water path.