Oil Absorbents Based on Melamine/Lignin by a Dip Adsorbing Method

Effective removal of oils and leakage chemicals from water is of significance in oceanography, environmental protection, and industrial production. Materials that can reduce environmental pollution are in high demand. Herein, we have developed a facile synthesis of ultralight, high-hydrophobic, and superoleophilic sponges (UHS sponges) through a dip adsorbing process based on lignin and commercially available melamine sponges. The obtained UHS sponges consist of an interconnected structure with high porosity and ultralow density (6.4 mg cm^–3). As the hydrophobic carbon coating of the skeleton and its microstructure trapping the air, the UHS sponge exhibits high-hydrophobicity and superoleophilicity, which are beneficial to its applications in oil–water separation. Besides lignin, other biomass like tannin is also suitable as the modification agent to prepare UHS sponges via a dip adsorbing method. As a result, this novel sponge exhibits excellent oil/water separation performance such as high selectivity, good recyclability, and oil absorption capacities up to 217 times of its own weight or 99 vol % of its own volume. We believe that this dip adsorbing method resultant sponge is highly promising as an ideal oil absorbent in oil spill recovery and environmental protection