Sustainable processing of waste polypropylene to produce high yield valuable Fe/carbon nanotube nanocomposites

摘要

With the increasingly serious environmental contamination and energy crisis, it is highly necessary that polyolefin-based waste plastics are converted into valuable materials by innovative upcycling processes. This study presents an environmentally benign and solvent-free autogenic process to produce sponge-like Fe/carbon nanotube nanocomposites by catalytic pyrolysis of waste polypropylene (PP) at 600 degrees C. The composition and morphology of the products were characterized by powder X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). The results show that the products are Fe/carbon nanotube nanocomposites with sponge-like structures, and the diameter of the carbon nanotubes is about 30 nm while the diameter of the Fe nanoparticles in the carbon nanotubes is also about 30 nm, which illustrates that the size of the Fe nanoparticles determines the diameter of the carbon nanotubes. Nitrogen adsorption-desorption measurements indicate that the Brunauer-Emmett-Teller (BET) surface area is calculated to be 197.6 m(2) g(-1), and the Barrett-Joyner-Halenda (BJH) adsorption cumulative volume of pores is up to 0.2860 cm(3) g(-1). Magnetic measurements at room temperature indicate that the values of saturation magnetization (62.7 emu g(-1)) and coercivity (187.3 Oe) of the sponge-like Fe/carbon nanotube nanocomposites are different from those of bulk Fe due to the broad distribution of carbon nanotubes and the small size of the Fe nanoparticles.