Enhanced Biochar Production via Co-Pyrolysis of Biomass Residual with Plastic Waste after Recycling Process

Abstract

Biomass pyrolysis for oil production results in biochar byproduct, whose characteristics can be improved by the reuse of waste plastics. While the plastic recycling process leads to a large amount of plastic waste that cannot be reused, this underutilized feedstock holds the potential for coprocessing with biomass, thereby increasing the likelihood of producing valuable biochar products. This study sought to evaluate how the inclusion of plastic waste influences the pyrolysis of biomass residue. To this end, sawdust and hardwood biomass were chosen as materials to investigate how the presence of plastics might alter the properties of the resulting chars. Synergies were observed among the biomass components, particularly in samples with higher lignin content from hardwood biomass, which resulted in increased biochar yields. The results showed that a 20% blend of plastic waste with wood at 300°C produced a solid char with a yield of 40% by weight. Co-pyrolysis of the biochar derived from blends of 20 wt. % PP with both sawdust and hardwood resulted in significant enhancement of various properties of the resulting biochar, including surface area, carbon content, hydrophobicity, and aromaticity. This enhancement had a favorable effect on the carbon content and calorific values of the biochar. These enhanced properties significantly contributed to the biochar’s capacity for sorbing substances like various heavy metals. It can be proved that this result showed the importance of the energy content of biochar and its potential use for renewable applications. The beneficial combined effect seen in the plastic blends can be credited to the interaction between the biomass and polymer components, resulting in the production of fewer volatile products at higher temperatures. It can be suggested that biochar from biowaste and plastic waste not only reduces environmental impact but also converts it into a valuable and eco-friendly product.