CO2-assisted pyrolysis of plastic wastes: A review

Abstract

CO₂-assisted pyrolysis is an effective method widely used in the chemical conversion of different raw materials to value-added products. In particular, CO₂-assisted plastic pyrolysis can not only produce various hydrocarbons but also reduce the environmental pollution of plastic wastes and effectively reduce the emission of greenhouse gases. This technology has great significance for the treatment of urban plastic wastes. Herein, the latest progress in the pyrolysis of plastic wastes in the presence of CO₂ is reviewed. Compared with typical pyrolysis in an inert environment (such as N₂ or Ar), it is found that CO₂ can change the type and yield of gas products, effectively inhibit the generation of benzene derivatives and polycyclic aromatic hydrocarbons (PAHs), and greatly prevent the reduction of catalyst activity. The conditions and catalysts required for CO₂-assisted pyrolysis of different plastic wastes should be selected according to the requirements of desired products. Combined with pyrolysis kinetics, the proposed mechanisms of CO₂-assisted plastic pyrolysis are introduced. Finally, the main issues of the current researches and the future development trend on CO₂-assisted catalytic pyrolysis are discussed.