Environmental-friendly and magnetic/silanized ethyl cellulose sponges as effective and recyclable oil-absorption materials.

Ethyl cellulose (EC), owing to its wide availability, environmental-friendliness, and intrinsic hydrophobicity/oleophilicity, was used as an absorbent material for the first time. The superhydrophobic magnetic EC sponges with low density and high porosity were facilely prepared via freeze-drying method. The superhydrophobicity and magnetism of the sponges were achieved by silanization EC with hexadecyltrimethoxysilane and mixing with ferroferric oxide (FeO) nanoparticles. The as-prepared magnetic silanized EC (MSEC) sponges showed stable superhydrophobicity (θ>150°, rolling contact angle: 7°) in several kinds of solutions. Furthermore, the sponges exhibited high separation efficiency and good mass absorption capacity for a wide variety of oils and organic solvents (37-51 times of their own weight). Benefitting from the robust superhydrophobicity and good self-cleaning property of the sponges, the absorption capacity could be well maintained upon repeated use, demonstrating the superior recyclability. These advantages made the sponges ideal absorbents for oil spillage cleanup.