Highly Efficient Amorphous Carbon Sphere-Based Superhydrophobic and Superoleophilic Sponges for Oil/Water Separation

In this experimental study, a commercially available polyurethane (PU) sponge coated with amorphous carbon spheres (ACSs) is investigated for oil/water separation. The ACSs synthesized using chemical vapor deposition are embedded in the PU sponge by a simple dip-coating method. The superhydrophobic ACS-PU sponge exhibits a water contact angle (WCA) of 156.2 ± 1° and a sliding angle <5°. The prepared sponge exhibits high absorption capacity, removal of oil spills from water, and demulsification of an oil-in-water emulsion. Absorption capacities of 32-68 times the ACS-PU sponge weight were obtained for different organic solvents and oils. It was found that the prepared ACS-PU sponge can effectively absorb oils under both static and turbulent conditions. Compared with the reported studies on the loading of different carbon materials in sponges for oil/water separation, ACSs in PU have a low loading percentage of ∼7 wt % and better absorption recyclability. The method proposes a simple and cost-effective preparation technique of highly hydrophobic and oleophilic ACS-PU sponges for effective oil/water separation.