Synergetic co-pyrolysis of waste Bakelite and Thevetia peruviana seeds: Insights from kinetics, thermodynamics, and product composition

Abstract

The growing environmental damage from plastic and biomass waste requires urgent improvements in co-pyrolysis with optimized reactors to efficiently convert wastes into valuable products. So, this study examines the synergetic kinetics and thermodynamics of co-pyrolysis of Bakelite and Thevetia peruviana (Kaner) seed blend (1:1 w/w) using thermogravimetric analysis at different heating rates (5–50 °C/min.) and temperatures (30–1000 °C), aiming to convert waste into valuable products, with pyrolytic waxy oil analyzed by FTIR and GC–MS. The weight loss of the blend (79.70 %) is higher by 19.36 % as compared to Bakelite alone (60.34 %). The synergistic interaction between Kaner seed and Bakelite reduces the activation energy of pyrolysis by 26.76 % from that required for Bakelite pyrolysis and by 16.13 % from that required for Kaner seed pyrolysis. The kinetic mechanism of thermal degradation remains unchanged for Bakelite (F₅) and its blend with Kaner seed (F₅), whereas Kaner seed exhibits a different degradation mechanism(F₄). The thermal degradation of the blend shows lower ΔG (466.990 kJ/mol) and ΔH (67.734 kJ/mol) and a higher ΔS (-1014.355 × 10⁻³ kJK⁻¹mol⁻¹) than both Bakelite and Kaner seed. The pyrolysis of the blend shows a 17.27 % increase in waxy oil yield compared to Bakelite alone. GC–MS analysis of pyrolytic oil shows a significant change in the composition of the oil obtained from the blended sample compared to the individual sample due to a synergistic effect, which is also supported by FTIR analysis. This study will help optimize the co-pyrolysis process and reactor design for real-scale applications.