Title : Sustainable conversion of waste printed circuit boards into phenol-rich pyrolysis oil through catalytic upgrading and bromine removal
Abstract:
Waste printed circuit boards (WPCBs) represent a significant secondary resource of carbonaceous materials; however, their recycling is challenged by the presence of brominated flame retardants and toxic organic compounds. This study explores the catalytic valorization of metal-free WPCBs through pyrolysis using zeolitic and alkaline catalysts for the generation of high-value chemical products and cleaner pyrolysis oil. Fixed-bed catalytic pyrolysis experiments were performed using ZSM-5, Ca(OH)?, and a combined catalytic system. The influence of catalysts on product distribution, oil composition, bromine removal, and reduction of undesirable oxygenated compounds was investigated using GC–MS, LC–MS, XRF, and physicochemical fuel characterization techniques. The incorporation of ZSM-5 enhanced selective aromatization and cracking reactions, increasing the phenolic fraction of pyrolysis oil from 54.44% to 72.08% while reducing undesirable heavy hydrocarbons and oxygen-containing compounds. Ca(OH)? exhibited effective bromine capture capability, achieving up to 69.79% bromine reduction, while the combined catalytic system further improved detoxification with 71.39% bromine removal along with reduced furan formation. The upgraded pyrolysis oils demonstrated improved fuel characteristics, including favorable viscosity and cetane number, indicating their potential for further refining into fuels and value-added chemicals. This work provides an integrated approach for sustainable WPCB management by combining waste minimization, hazardous component removal, and recovery of phenol-rich chemical resources within a circular economy framework.
