Treatment by a nanometallic Ca/CaO composite has been found to selectively hydrophilize the surface of
polyvinyl chloride (PVC), enhancing its wettability and thereby promoting its separation from E-waste
plastics by means of froth flotation. The treatment considerably decreased the water contact angle of PVC,
by about 18◦. The SEM images of the PVC plastic after treatment displayed significant changes in their
surface morphology compared to other plastics. The SEM-EDS results reveal that a markedly decrease
of [Cl] concentration simultaneously with dramatic increase of [O] on the surface of the PCV samples.
XPS results further confirmed an increase of hydrophilic functional groups on the PVC surface. Froth
flotation at 100 rpm mixing speed was found to be optimal, separating 100% of the PVC into a settled
fraction of 96.4% purity even when the plastics fed into the reactor were of nonuniform size and shape.
The total recovery of PVC-free plastics in E-waste reached nearly 100% in the floated fraction, significantly
improved from the 20.5 wt% of light plastics that can be recovered by means of conventional wet gravity
separation. The hybrid method of nanometallic Ca/CaO treatment and froth flotation is effective in the
separation of hazardous chlorinated plastics from E-waste plastics