Polymer foam fabricated via surfactant foaming method enables high-performance solar interfacial evaporation

Solar interfacial evaporation is considered as a low energy consumption, low cost, and sustainable desalination technology. However, its practical application is still limited by complex preparation processes and low photothermal conversion efficiency. In this work, we report novel polymer foam (Agar/SA/GO-Ag composite foam). It is prepared by simple and convenient surfactant foaming and in-situ reduction methods and consists of graphene oxide (GO) and silver nanoparticles (Ag NPs) (photothermal conversion medium) as well as Agar and sodium alginate (SA) (basic skeleton) for use in solar-powered interfacial evaporation systems. The prepared foam has excellent wettability and achieves 96.7% light absorption in the full spectrum range. A high evaporation rate of 2.55 kg·m ⁻² ·h ⁻¹ and a high evaporation efficiency of 97.3% were obtained under the conditions of simulated sunlight (1.0 kW·m ⁻² ). Moreover, the foam exhibits good reusability in a 10-cycle test without obvious attenuation in evaporation performance. Foam is used for seawater desalination and wastewater purification, and the treated water meets the water quality standards of the World Health Organization (WHO) and the United States Environmental Protection Agency (USEPA). In short, this work demonstrates a sustainable strategy for low-cost and efficient solar-powered clean water production.