Polyethylene terephthalate (PET) waste to carbon materials: Theory, methods and applications

Polyethylene terephthalate (PET polymer) is the main ingredient in clear bottles containing water and other liquids such as hand sanitizers. Due to the increasing use of these disposable bottles, especially during the COVID-19 pandemic, the production of PET waste is a significant challenge for the world. PET waste can be considered a suitable raw material for producing activated carbon and other nanoporous carbons due to its 11% fixed carbon content, low ash and impurity content, and oxygen content of about 30%. However, due to limited yield and competing recycling methods, conversion into carbonaceous sorbents by traditional methods appears to be impractical. This article addresses various conventional and novel methods for activating PET to determine the current situation of this technology and the reasons for the low interest in it compared to other polymeric wastes such as scrap tires. A comparison is made between the properties and performance of PET with other polymeric wastes for these purposes. The adsorptive applications of PET-ACs in wastewater treatment, flue gas cleaning, gas storage, and energy storage in supercapacitors are also discussed.