Recyclable magnetic superhydrophobic straw soot sponge for highly efficient oil/water separation.

A simple and low-cost route to fabricate durable superhydrophobic magnetic polyurethane sponge was obtained by immersing a polyurethane sponge in a colloidal suspension of straw soot and magnetic nanoparticles. The as prepared sponge was used for separation of oil/water mixture. XRD, FT-IR, VSM, SEM and contact angle measurement analysis were used for characterization the materials. The effects of different stabilizer or surfactants (cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS) and polyethylene glycol 6000 (PEG 6000)) on the morphology and geometrical structure of magnetic nanoparticles were investigated. For increasing the hydrophobic property of the surface, the sponge was further modified using PDMS. Results indicated that this matter can promote interfacial interactions between the sponge surface and oil. The prepared sponge showed excellent superhydrophobicity with water contact angle as high as 154°. Experiments showed that the amount of the absorbed oil was about 30 times of sponges own weight, it has our 30 times recyclability and the advantage of magnetic separation.