Thermochemical Valorization of Waste Plastic for Production of Synthetic Fuels, Fine Chemicals, and Carbon Nanotubes

Globally, approximately 300 million metric tonnes of plastic waste are generated annually, and over 90% of them are either disposed to the landfill or incinerated. Though there are commitments to reduce waste plastics, it has its limitations. In this review, the various types of thermochemical processes (pyrolysis, gasification, and hydrothermal liquefaction) used for plastic waste upcycling are first introduced. The production of synthetic fuel, fine chemicals, and carbon nanotubes through these processes are then discussed, with the effects of each factor scrutinized. Technical challenges of the production using plastic waste and how it can be overcome are then highlighted. Economical and environmental assessment of the processes are also analyzed to determine whether such processes are viable for upcycling of waste plastic, closing the carbon economy loop.