Solar-mediated oil-spill cleanup by a carbon dot-polyurethane sponge

Development of efficient, inexpensive, and environmentally-benign technologies for oil-spill cleanup is essential in light of the prevalence of spilling incidents, and their adverse environmental impact. We report the synthesis of a new composite material for solar-mediated oil absorbance and removal comprising highly porous polyurethane sponge embedded with a polydimethylsiloxane (PDMS) layer and carbon dots. The excellent oil cleanup capabilities of the material emanate from integrating the distinctive features of the three components. The PU sponge endows resilient, highly porous morphology, while the PDMS constitutes a highly hydrophobic internal layer facilitating oil absorption. The carbon dots have a particularly important role, exhibiting efficient sunlight absorbance and converting the irradiation to heat. The dissipated heat induced lower oil viscosity and concomitant greater uptake by the porous sponge. Altogether, excellent solar-mediated oil absorption and recovery, and good recycling capacity were accomplished. The simple synthesis utilizing inexpensive and environmentally-benign constituents, chemical stability, and recyclability make the carbon dot-PDMS-polyurethane composite sponge an attractive and practical vehicle for oil-spill cleanup, oil storage, and recovery applications.