Composite sponges fabricated by silk fibers and alginate for efficient oil/water separation

The fabrication of advanced oil/water separation materials with integrated properties of mechanical robust, high efficiency, and low cost is a long-standing challenge. O-SM/ALG (octadecylamine modified silk microfibers/calcium alginate) sponges were synthesized in this paper through a facile process. The as-fabricated O-SM/ALG sponges possess interconnected porous structure, high mechanical durability, hydrophobicity, and lipophilicity that favored for oil/water separation. As oil absorbents, the O-SM/ALG sponges displayed excellent water repellence, exhibited high absorption capacity for various oils and organic solvents (the saturated absorption capacity was 13.1–24.6 times of its own weight), and showed good recyclability (reused > 20 cycles with remained high absorption efficiency). Furthermore, the O-SM/ALG sponges could also be applied as a filter to effectively and selectively separate oils from the oil/water mixture, being a promising candidate for the treatment of oily wastewater.