Polybenzoxazine-Functionalized Melamine Sponges with Enhanced Selective Capillarity for Efficient Oil Spill Cleanup

Severe environmental and ecological issues arising from frequent oil spill accidents have been great worldwide concerns. Considering the abruptness, complex condition, and long-term perniciousness of the spilled oil, the development of economic and versatile materials to quickly remove oil contaminants, especially for oil with high viscosity from a large water body, is of significant importance but remains a big challenge. Herein, we demonstrated a facile strategy to fabricate a versatile hierarchical structured sponge with superhydrophobicity and powerful oil capillarity via the in situ polymerization of a novel phenolic resin (polybenzoxazine) composite open-cell sponges. The tunable hierarchical structures of the as-prepared sponge significantly improved its water repellence and oil capillarity; meanwhile, a plausible mechanism is also proposed. With the merits of high porosity, excellent water repellence, enhanced oil capillarity, and robust mechanical stability, the obtained sponge exhibited an intriguing oil spill cleanup performance with fast oil absorption speed, good recyclability, and high absorption capacity. Besides that, the modified sponge could also be utilized for the separation of oil/water mixture with individual phase and the surfactant-stabilized emulsion solely under the drive of gravity. The robust oil/water separation performance, low cost, and facile synthesis strategy make the resultant sponges a competitive material for the large-scale oil spill emergency remediation.