The large amounts of polyurethane foam wastes (PUFWs) produced in the automobiles, buildings, and furniture industries cause many environmental problems. Therefore, the recycling of PUFWs has acquired great interest worldwide. In this study, the PUFWs were converted to new nanocomposite. The chemical modification of PUFWs was conducted through reflux with potassium permanganate in 0.1 M H2SO4. The produced PUF-COO@MnO2 nanocomposites was characterized by scanning electron microscope, energy-dispersive X-ray spectrometry, X-ray diffraction, and Magnetic susceptibility. PUF-COO@MnO2 has been used for the removal of cationic (Methylene blue) and anionic (Trypan blue) dyes from industrial wastewater. The antibacterial effect of PUF-COO@MnO2 was also examined against Gram-positive and Gram-negative bacterial strains. The adsorption capacities of PUF-COO@MnO2 for tested dyes were 277 and 269 mg/g. Moreover, PUF-COO@MnO2 showed a potent antibacterial action against B. cereus (8.8 mm) followed by S. aureus (7.5 mm) and E. coli (7.1 mm). It was concluded that PUF-COO@MnO2 can be employed as antibacterial low-cost material and for the removal of synthetic dyes from industrial effluents.