A robust anti-fouling multifunctional aerogel inspired by seaweed for efficient water purification

Developing effective and green methods to treat large volumes of oily sewage is a significant challenge for aquatic pollution. In this study, an environmentally friendly, economical, self-cleaning, and multifunctional sodium alginate (SA)-tannic acid (TA) aerogel for emulsion separation was prepared via simple freeze-drying and in-situ gelation methods. The microstructure and chemical composition of the SA-TA aerogel are characterized by SEM, EDS, FT-IR, and XPS. As a result, the SA-TA aerogel has an interconnected 3D network structure, high porosity and rough microstructure. Furthermore, the SA-TA aerogel behaves a robust super hydrophilicity, underwater superoleophobicity, anti-crude oil-fouling performance and self-cleaning effect. Thus, it has excellent performance to separate oil-in-water emulsion with high water flux only under gravity and shows terrific cyclic stability. It is worth to note that SA-TA aerogels show improved mechanical properties, stable wettability in various chemical environments, and excellent adsorption properties for soluble dyes, which enable them to be used in complex actual water treatment.