Advances in Catalytic Pyrolysis of Mixed Plastic Waste with Algal Biomass: A Review on Sustainable Biofuel Production and Carbon Capture

Abstract

The increasing demand for fuel and the growing environmental challenges posed by plastic waste have accelerated the development of alternative strategies for converting synthetic polymers into value-added products. Catalytic pyrolysis has emerged as a promising thermochemical technique to recover fuel and monomer precursors from plastic waste under inert conditions, and this approach can be further improved through the integration of algal biomass. This review provides an in-depth analysis of algae-assisted catalytic pyrolysis, emphasizing the synergistic interactions between plastic polymers, algae species-particularly Chlorella vulgaris-and various catalysts including ZSM-5, red mud, Ni/SiO2, Co-Mo/Al2O3, and natural zeolites. The study explores the roles of these catalysts in improving reaction pathways, cracking efficiency, product selectivity, and dechlorination during the co-pyrolysis process. Algal biomass offers several advantages, including its high lipid and oxygen content, mineral composition, and capacity to act as a hydrogen donor, thereby promoting hydrocarbon formation and enhancing fuel quality. Moreover, algae-derived biochar can serve as a renewable and lowcost catalyst support. The review also presents a bibliometric analysis, highlighting trends in algae-integrated pyrolysis research, and discusses the influence of process parameters, reactor configurations, and catalyst regeneration methods. Techno-economic and environmental assessments demonstrate that algae-assisted catalytic pyrolysis offers an efficient and sustainable pathway for managing plastic waste, producing cleaner fuels, and advancing circular economy goals. Future research should focus on scaling up technology, optimizing catalyst design, and enhancing the energy integration between pyrolysis units and algae cultivation systems.