tration, temperature and time of treatment are
required to achieve a significant difference in
hydrophobicity between PVC and PET particles.
For a variety of PVC/PET samples tested in our
laboratory, the 15-30 min of alkaline treatment
using 2 wt% NaOH solution at 70-80°C allowed
for selective flotation separation of PVC from PET
particles [ 171. Unfortunately, as observed in our
laboratory, such ‘optimum’ alkaline solutions
sometimes become too aggressive for the PVC
from certain waste streams. Fig.