High-purity H2 production from mixed PVC/PET plastic wastes through tandem hydrothermal depolymerization and aqueous phase reforming

Mixed plastic wastes are posing substantial challenges to the environment due to their mass production and difficulty in separation, especially mixed polyvinyl chloride/polyethylene terephthalate (PVC/PET) plastic wastes. In this work, a novel tandem thermochemical process including hydrothermal depolymerization of mixed PVC/PET plastic wastes, and subsequent catalytic aqueous phase reforming (APR) of hydrolysate solution was developed. The activated carbon derived from PVC (PVC-AC) supported Ru catalysts were prepared and successfully used in the catalytic APR of hydrolysate solution for high-purity H 2 production. Besides, the presence of NaOH realized in-situ capture of CO 2 in APR process, which promoted the water-gas shift reaction and inhibited methanation reactions. As a result, a high H 2 yield of 12.23 mol/kg Plastic with H 2 concentration of ca. 98% was obtained via tandem hydrothermal conversion of mixed PVC/PET plastic wastes. The by-products from the entire tandem process including the terephthalic acid (TPA) and sodium chloride (NaCl) were separated and purified for further industrial application. This work provided a sustainable route for conversion of mixed plastic wastes into value-added fuel.