Construction of a Superhydrophobic Sodium Alginate Aerogel for Efficient Oil Absorption and Emulsion Separation

Bio-based aerogels serve as potential materials in separation of oil/water mixtures. Nevertheless, there remain some key challenges, including expensive/toxic organic cross-linkers, unpromising reusability, and poor performance in emulsion separation. Hereby, a novel, robust, and superhydrophobic sodium alginate/graphene oxide/silicon oxide aerogel (SA/GO/SiO₂-M) was fabricated by simple calcium ion cross-linking self-assembly, freeze-drying, and chemical vapor deposition methods based on the renewable and abundant raw materials. The as-prepared SA-based aerogel possesses high absorbency for varieties of organic solvents and oils. Importantly, it shows high efficiency in the separation of surfactant-stabilized water-in-oil emulsions. SA/GO/SiO₂-M aerogels display excellent reusability in both absorption and separation because of their good mechanical properties in the air and oil phase, and the mechanism in emulsion separation is discussed. This study shows that SA/GO/SiO₂-M aerogels are a promising material in treating oil contaminants from different fields.