Oil‐absorbent polyurethane sponge coated with KH‐570‐modified graphene

Polyurethane (PU) sponge has become a preferred oil adsorbent in recent oil‐spill accidents. To make the sponge superhydrophobic and superoleophilic, this study used graphene (GN), which was modified with γ‐methacryloxypropyl trimethoxy silane (KH‐570), to coat the PU sponge (called the KH–GN sponge). This study showed the best loading capacity (11.96%) of the KH‐570‐modified GN on the sponge. The contact angles of the KH–GN PU sponge were 161° for water and 0° for soybean, diesel, and pumping oil. It had good selectivity for oil over water, and the KH–GN sponge achieved adsorption equilibrium within a few seconds. The absorption capability of the KH–GN sponge was up to 39 times greater. Additionally, the KH–GN PU sponge could be reused for oil–water separation for more than 120 cycles without losing its superhydrophobic and superoleophilic properties. Therefore, the sponge prepared in this study could be a desirable material for the cleanup of oil spills.