Progress and perspective for conversion of plastic wastes into valuable chemicals

Today, discarded plastics in nature have caused serious white pollution, however these plastic wastes contain abundant carbon resources that could serve as the feedstock to produce commodities. Because of this, it is requisite to convert these plastic wastes into valuable chemicals. Herein, the state-of-the-art techniques for plastic conversion are divided into two categories, those performed under violent conditions and mild conditions, in which the conversion mechanisms are discussed. The strategies under violent conditions are closer to practical application thanks to their excellent conversion efficiencies, while the strategies under mild conditions are more environmentally friendly, showing enormous development potential in the future. We summarize in detail the pyrolysis, hydropyrolysis, solvolysis and microwave-initiated catalysis for bond cleavage in plastic wastes at temperatures ranging from 448 to 973 K. Also, we overview the photocatalysis, electrocatalysis and biocatalysis for bond cleavage in plastic wastes at near and even normal temperature and pressure. Finally, we present some suggestions and outlooks concerning the improvement of current techniques and in-depth mechanisms of investigation for conversion of plastics into valuable chemicals.

Automated summary

The conversion of discarded plastics into valuable chemicals is an important problem to solve. Different conversion techniques can be categorized into violent conditions and mild conditions, with the former showing better conversion efficiencies and the latter being more environmentally friendly with great potential for future development. This review summarizes the state-of-the-art techniques for the conversion of plastics, including pyrolysis, solvolysis, microwave-initiated catalysis under violent conditions, and photocatalysis, electrocatalysis, biocatalysis under mild conditions. Suggestions and outlooks for the improvement of current techniques and in-depth mechanisms of investigation are also provided.