ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Multidimensional approach to waste EPDM and walnut shell co-pyrolysis: kinetic, thermodynamic, artificial neural network, and solid product characterization

Burcu Kiren and Esin Apaydın-Varol

Faculty of Engineering, Chemical Engineering Department, Eskişehir Technical University, İki Eylül Campus, 26555, Eskişehir, Turkey

E-mail: eapaydin@eskisehir.edu.tr

Received: 23 July 2025  Accepted: 27 September 2025

Abstract:

The utilization of waste materials for the production of carbonaceous products through thermochemical conversion offers an environmentally sustainable and cost-effective approach for managing industrial and agricultural wastes, while also addressing the global demand for renewable energy sources. This study explores the laboratory-scale pyrolysis characteristics and kinetic behavior of co-pyrolysis of waste Ethylene Propylene Diene Monomer (EPDM) and walnut shell (WS), aiming to contribute to sustainable energy recovery from waste. Pyrolysis was conducted at 500 °C in a N₂ atmosphere with a heating rate of 10 °C/min, resulting in yields of 52.3% and 28.7% for waste EPDM and WS, respectively. A synergistic effect was observed on solid product yields and quality via various analytical methods. Kinetic modeling using Kissinger, KAS, FWO, and Starink methods was performed to determine activation energies and thermodynamic parameters, with average activation energies for WS, waste EPDM, and their blends (wt.%, 1:1) falling within the 137.5–140.8 kJ/mol range across all models. Additionally, an artificial neural network model was developed for process prediction, achieving a high R² (> 0.9999). The study highlights the necessity of simultaneous pyrolysis of biomass and elastomers to optimize energy recovery, mitigate environmental impact, and advance waste-to-energy technologies.

Graphical abstract

Keywords: Co-pyrolysis; Walnut shell; Waste EPDM; Kinetics; Thermodynamics; ANN

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-025-04423-8

Chemical Papers 80 (1) 701–726 (2026)