Facile aqueous fabrication of superhydrophobic carbon black-based photothermal melamine sponge for multi-state oil cleanup

In light of the complex and diverse characteristics of multi-state oil, the development of superhydrophobic photothermal porous absorbents (SPPAs) with excellent oil selectivity is of great ecological importance to the water remediation. Still, simple, eco-friendly and scalable fabrication approaches of SPPAs remain challenging. Herein, a novel superhydrophobic photothermal melamine sponge (CWHM sponge) was prepared via a straightforward two-step dip-coating process in carbon black-based aqueous dispersion. The as-prepared sponge with excellent superhydrophobicity (water contact angle of 159.0 & ring;) was demonstrated to be an efficient sorbent for various low-viscosity oils and organic solvents, with high absorption capacity (31.5-68.5 g/g) and good reusability. More importantly, the surface temperature of CWHM sponge can rapidly increase to 81.7 degrees C in 15 s when exposed to 1.0 kW/m2 sunlight irradiation, owing to the carbon black-based coating that imparts the sponge with exceptional photothermal conversion efficiency. Consequently, CWHM sponge dramatically accelerates the crude oil recovery process by rapidly heating and reducing the oil viscosity, and the maximum absorption capacity of crude oil can reach as high as 67.8 g/g. Based on the environmentally friendly fabrication and exceptional oil/water separation performance, this work provides a promising absorbent for the remediation of complex oily polluted waters.