Kinetic analysis of PET methanolysis by using biomass-based heterogeneous catalysts. Towards sustainable chemical plastic recycling

Environmental pollution, particularly from non-biodegradable plastics like polyethylene terephthalate (PET), is a significant challenge for the scientific community. Methanolysis offers a promising route for PET chemical recycling but typically requires harsh conditions. This study explores novel aluminum and calcium-based catalysts synthesized with rice husk biochar and pectin to enhance PET methanolysis efficiency. The kinetic investigations reveal the superior catalytic activity of biochar-assisted catalysts, with calcium-based materials exhibiting remarkable performance, surpassing those prepared with pectin. The most active material (CaB) demonstrated exceptional performance, displaying a 500% increase in the kinetic constant compared to the thermal reaction. This material showed an activation energy of 79.33 kJ mol⁻¹. In contrast, activation energies higher than 90 kJ mol⁻¹ were obtained for the other materials and around 131 kJ mol⁻¹ for the thermal reaction. Moreover, the mentioned calcium-based catalyst showed superior stability over five runs, with a yield higher than 90%, revealing their potential for sustainable PET waste management. This research underscores the potential of calcium-based catalysts for sustainable PET waste management, offering a pathway towards more sustainable and energy-efficient PET recycling, leveraging biomass-based catalysts.