A comprehensive review of sustainable valorisation of lignocellulosic biomass and plastic waste into biofuels and chemicals via co-liquefaction

Liquefaction stands out as a promising strategy within the bioeconomy, offering a pathway to convert waste into valuable fuels and products. However, bio-oil from biomass liquefaction has high oxygen content and poor calorific value, limiting its practical applications. To overcome these challenges, one promising approach is the co-liquefaction of oxygen-rich biomass with hydrogen-rich plastic, offering a sustainable means of producing high-quality oil. This review explores lignocellulosic biomass and plastic co-liquefaction, highlighting its behaviours, reaction pathways, and process parameters' effects. The co-liquefaction process offers significant advantages over lignocellulosic biomass or plastic liquefaction in improving oil quality and yield. Comprehensive studies on the effect of process parameters and reaction pathways are much needed to optimise the conditions and design an efficient and effective co-liquefaction process for lignocellulosic biomass and plastics. Life cycle assessment (LCA) and techno-economic assessment (TEA) are two viable approaches to evaluating the potential environmental impacts and economic performance, respectively. Finally, lignocellulosic biomass and plastic waste co-liquefaction is a viable approach to managing waste and producing valuable materials, which promotes significant values, including resource efficiency, waste reduction, environmental sustainability, and economic opportunities.