Surface change of microplastics in aquatic environment and the removal by froth flotation assisted with cationic and anionic surfactants

•Six months of incubation in aquatic environment can hydrophilize microplastics.•Surface oxidation and sediment deposition are the hydrophilization mechanism.•Cationic and anionic collectors are used for the flotation removal of microplastics.•The hydrocarbon chains of collector laminate and wrap on microplastics surfaces.•The activation by metal ions conserves collector and improves flotation efficiency.