The separation of an individual plastic from a plastics mix is crucial in plastic recycling management. The selected plastics available in municipal and industrial wastes, including polycarbonate (PC), poly oxy methylene (POM), and acrylonitrile butadiene styrene (ABS) pre-irradiated with microwaves for different microwave power %’s at several irradiation times. The irradiated plastics subsequently conditioned with selected depressants with different concentrations before introducing into the flotation tank. The effects of the above-mentioned parameters evaluated on the float-sink behavior of the studied plastics. It revealed that the pre-microwave irradiation of the plastic surface was influential on the float-sink performance of the studied plastics. The microwave irradiation changed the numbers, capacity, and concentration of the active sites on the plastic surface. The microwave irradiation reduced θ (contact angle) values of the un-conditioned plastic surface with studied depressants for all used plastics resulted in increasing the hydrophilic property of the surface of the plastics. It concluded that different mechanisms, individually or together, involved for depressant adsorption-desorption on a plastic surface. The microwave pre-irradiation for some plastics and depressants was beneficial for plastic flotation whenever for other samples, it helped the plastic to sink at the bottom of the flotation tank. The suggested equations by Design-Expert® software to predict the plastic flotation % versus studied parameters conformed with experimental results appropriately.

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