Fast microwave carbonization of aluminum-coated plastic wastes and perspectives: The examples of CDs and snack bags

Abstract

Aluminum-coated plastics, such as CDs and snack bags, are widely used and consumed around the world. Since millions of CDs and trillions of snack bags end up in landfills and oceans as plastic waste every year, we suggest here an easy, fast, and cost-effective method for transforming this significant volume of garbage into added-value carbon using microwave technology. The proposed method differs from existing time- and energy-consuming pyrolytic processes employed in the traditional carbonization of this sort of waste. Conceptually, direct irradiation of the aluminum-coated plastic items in a domestic microwave oven heats up the metallic coating, thus triggering carbonization of the plastic substrate. The resulting carbon, which is characterized by means of X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) techniques, has structural similarities to carbons produced from CDs and snack bags using pyrolytic methods. In other words, the microwave technique produces similar effect, but it is faster and more energy efficient. We finally demonstrate some practical uses of the derived materials in gunpowder production, carbothermal production of metals and grey paint formulations.