▎ 摘　　要

Graphene oxide is an outstanding nano collector for removing heavy metal ions from wastewater via ion flotation. In this current work, the mechanism for enhancing Cu(II) removal via adjusting the oxidation degree of nano collector was first proposed when graphene oxide was selected as nano collector of ion flotation. A series of graphene oxide samples with various degrees of oxidation were prepared and characterized by zeta potential, fourier transform infrared spectroscopy, particle size measurement and water contact angle. Furthermore, the variations of initial solution pH, ionic strength, cetyl trimethyl ammonium bromide dosage and gas flowrate were studied systematically. The results showed that Cu(II) removal could be enhanced by increasing the oxidation degree of nano collector (graphene oxide). On the one hand, more oxygenous functional groups were introduced when increasing the oxidation degree of graphene oxide, which gave rise to a higher Cu(II) removal. On the other hand, graphene oxide with higher degree of oxidation were more easily to flocculate into bigger flocs, making it easier to collide with and attach to bubbles, thus achieving efficient separation with the aid of cetyl trimethyl ammonium bromide to enhance its affinity towards bubbles. (c) 2021 Elsevier Ltd. All rights reserved.