Developing affordable, long-lasting, and effective membranes is essential for the treatment of oily wastewater, which has become a substantial problem. In this study, an affordable and environmentally-friendly hydrophobic microfibers were designed. Polystyrene wastes were recycled into a functional hydrophobic microfiber. ZnO, CuO, and CuO-ZnO nanoparticles were synthesized using pine pollen waste via green approach. Thereafter, green synthesized nanoparticles were incorporated into recycled polystyrene to fabricated an efficient microfiber. Fabricated microfibers were characterized via FT-IR and XRD, SEM and SEM–EDS. Water contact angle of the polystyrene nanofibers were increased from 123.5° to 139.1° by metal oxide incorporation. Separation efficiency of the polystyrene microfiber was also improved by addition of green synthesized CuO to 81.84%. Notably, these environmentally-friendly membrane nanocomposites can be used in water–oil separation applications successfully.