Solar-driven interfacial evaporation technologies for food, energy and water: Fid-Bau Portal

Solar-driven interfacial evaporation technologies for food, energy and water

Solar-driven interfacial evaporation technologies use solar energy to heat materials that drive water evaporation. These technologies are versatile and do not require electricity, which enables their potential application across the food, energy and water nexus. In this Review, we assess the potential of solar-driven interfacial evaporation technologies in food, energy and clean-water production, in wastewater treatment, and in resource recovery. Interfacial evaporation technologies can produce up to 5.3 l m^–2 h⁻¹ of drinking water using sunlight as the energy source. Systems designed for food production in coastal regions desalinate water to irrigate crops or wash contaminated soils. Technologies are being developed to simultaneously produce both clean energy and water through interfacial evaporation and have reached up to 204 W m^–2 for electricity and 2.5 l m^–2 h^–1 for water in separate systems. Other solar evaporation approaches or combinations of approaches could potentially use the full solar spectrum to generate multiple products (such as water, food, electricity, heating or cooling, and/or fuels). In the future, solar evaporation technologies could aid in food, energy and water provision in low-resource or rural settings that lack reliable access to these essentials, but the systems must first undergo rigorous, scaled-up field testing to understand their performance, stability and competitiveness.

Interfacial solar evaporation technologies use solar energy to drive water evaporation. This Review discusses the use of these technologies to manage wastewater, to recover resources and to produce clean water, food and energy.

Evaporation–condensation purifiers (a common solar interfacial evaporation purifier design) use solar energy to generate fresh water at 0.4–5.3 l m^–2 h^–1, but are limited by water’s vaporization enthalpy (2,400 kJ kg^–1). Solar steam-driven membrane desalination lowers the salt–water separation energy to 5.76 kJ kg^–1, producing fresh water at up to 81 l m^–2 h^–1 under 12-sun illumination.

Through the implementation of various anti-fouling measures, engineered solar evaporators show strong resistance to salt, biofouling and organic contamination, with month-long stability in the laboratory. Next-generation systems should be scaled up and monitored in the field over several months to assess real-world viability.

Solar evaporation technologies could supply high-quality fresh water for irrigation and soil remediation, aiding agriculture in coastal areas.

Energy can be harvested from water evaporation through thermoelectric, pyroelectric, salinity gradient and hydrovoltaic power generation, producing 1–10 W m^–2. Solar photovoltaic–evaporation hybrid systems are better suited to large-scale applications, generating around 100–200 W m^–2 of electricity.

Evaporators can extract dilute critical resources from complex water matrices. Co-generation of multiple resources through interfacial evaporation could enhance the energy efficiency of the processes, but require further study and development.

Small-scale systems are well tested at the laboratory scale and are suitable for personal or household use, but large-scale systems are essential for industrial applications. Successful commercialization of solar evaporation technologies will require scaling up, reducing costs and meeting regulatory standards.