Superhydrophobic starch-based cryogels modified with silylated magnetic nanoparticles for oil spill cleanup

Superhydrophobic smart adsorbents have attracted wide attention for the cleanup of oil spill that endangers the aquatic ecosystem. Herein, a super-water-repellent coating (HOS/Fe3O4) was achieved through hydrolytic condensation of hexadecyltrimethoxysilane and tetraethyl orthosilicate in the presence of Fe3O4 nanoparticles. The coating was then introduced onto the surface of starch cryogel (SC) by spray-coating technique to fabricate the superhydrophobic and magnetic starch-based adsorbent (HOS/Fe3O4@SC). The surface chemical composition and hierarchical micro/nanostructures that contribute to the high water contact angle (>151°) and low sliding angle (<5°) of the as-obtained material were characterized in detail. The HOS/Fe3O4@SC exhibited excellent water repellent, self-cleaning, and anti-fouling properties. The structural support and stable chemical bonding endow the material with good mechanical and chemical durability. The HOS/Fe3O4@SC also possessed reasonable adsorption capacities to various organic solvents, and its oil absorption kinetics was also comprehensively studied. The HOS/Fe3O4@SC can be applied for heavy oil absorption underwater and magnetically guided oil slick cleaning. This novel starch-based absorbent exhibits promising application in tackling oil contamination in complex environments.