Co-pyrolysis of plastic waste and macroalgae Ulva lactuca, a sustainable valorization approach towards the production of bio-oil and biochar

To address the pressing demand for sustainable energy in light of environmental challenges, this study explored the synergetic effects of the co-pyrolysis of polyethylene terephthalate (PET) and Ulva lactuca macroalgae to yield bio-oil and biochar. The objective is to enhance the bio-oil quality for wider usability and to combat marine pollution. By employing co-pyrolysis, notable progress has been achieved in bio-oil yield and quality, particularly in hydrocarbon content, through the integration of PET. The highest bio-oil yield of 37.91% was achieved under optimal conditions at 500 °C with a feedstock mixture consisting of 40% U. lactuca and 60% PET. Under these conditions, the bio-oil exhibited a significant increase in hydrocarbon content, reaching 57.16%, which is essential for improving its energy potential. Biochar quality was also enhanced, with the biochar from a 70% U. lactuca and 30% PET blend showing a BET surface area of 20.18 m 2 /g, compared to the initial 1.38 m 2 /g of raw U. lactuca , indicating improved surface properties. This study presents a sustainable energy generation and environmental preservation approach, underscoring the potential of synergistically utilizing marine resources and plastic waste. • Co-pyrolysis of Ulva lactuca and PET enhances bio-oil yield and quality. • Optimal bio-oil yield of 37.91% at 500°C with 40% U. lactuca and 60% PET. • Synergetic effects of PET integration improve hydrocarbon content in bio-oil. • Reduced biochar formation improves BET surface area and mean pore diameter. • Sustainable valorization approach addresses both energy needs and marine pollution.