An intelligent superhydrophobic absorbent with electrothermal conversion performance for effective high-viscosity oil removal and oil–water separation

Functionalized superwetting materials that are able to deal with the contamination problems of industrial and domestic oily wastewater are urgently demanded in the field of oil–water separation. In this work, we fabricated superhydrophobic absorbent with excellent electrothermal conversion performance through the liquid-phase reduction and hierarchically assemble methods. The adhesive layer of poly-dopamine (PDA), Cu/carbon microspheres composites (Cu/CMSs) and the fluoride-free hydrophobic reagents were successively assembled on the absorbent cotton to obtain the intelligent absorbent with excellent superhydrophobicity (WCA = 154°), satisfactory oil–water separation efficiency (> 98.3%) and high oil absorption capacity (12–20 g/g). Surprisingly, this intelligent absorbent displayed an excellent electrothermal conversion capacity, which provided the basis for the collection of high-viscosity oil and the low-melting solid oil. On the basis of the excellent electrothermal conversion performance, it also could be utilized as a filter to effectively realize the continuous separation process of high-viscosity crude oil/water mixture under low-voltage conditions. Therefore, this intelligent absorbent possesses broad application prospects in high-viscosity oil–water separation, oily wastewater treatment, oil spill cleaning, crude oil extraction, petrochemicals and other fields.Graphical Abstract