Control of the fate of toxic pollutants from catalytic pyrolysis of polyurethane by oxidation using CO₂

In automotive industry, plastic consumption has substantially increased due to its affordability, durability, and lightness. However, the massive generation of plastic wastes from the automotive industry becomes a growing environmental concern. Current disposal methods of end-of-life vehicles (ELVs) are incineration and landfilling, but these methods generate toxic chemicals and leachate into the environment. To propose more sustainable disposal platform for ELVs, this study used a pyrolysis process using CO₂ as a reaction medium. As a case study, automotive seat form (ASF) in ELVs was disposed and valorized through the CO₂-assisted pyrolysis. ASF, composed of polyurethane, generated harmful aromatic compounds during pyrolysis process such as benzene, aniline and their derivatives. To convert harmful chemicals into value-added syngas (H₂ and CO), catalytic pyrolysis of ASF was performed using a nickel catalyst. Effects of both CO₂ and nickel catalyst showed 89.9 wt.% reduction of toxic chemical production by converting them into syngas, as comparing to pyrolysis without Ni catalyst. Gas-phase-reaction between CO₂ and pyrogenic products from ASF resulted in more than 200 times of CO production. Also, CO₂ suppressed catalyst deactivation. Therefore, this study suggested that CO₂ and plastic waste from ELVs can be converted to value-added products through CO₂-assisted catalytic pyrolysis. Copyright © 2022 Elsevier B.V.