Using CO₂ to mitigate evolution of harmful chemical compounds during thermal degradation of printed circuit boards

In this study, CO₂ was used as a reaction medium in the pyrolysis of printed circuit boards (PCBs), thus providing a novel route to mitigate the evolution of harmful chemical species during the thermal degradation of PCBs. For example, this study showed that CO₂ acts as an effective carbon scavenger during the pyrolysis of PCBs. CO₂ facilitated the thermal cracking of volatile organic compounds (VOCs) that evolved from the thermal degradation of PCBs. As a result, CO₂ mitigated the evolution of various harmful pollutants such as phenol and benzene derivatives, PAHs and brominated pollutants, which resulted in the increased generation of syngas (H₂ and CO). This study indicates that using CO₂ as a reaction medium could lead to the development of a more environmentally benign process for the thermal treatment of PCBs and other harmful and/or refractory wastes.