Synergism, pyrolysis performance, product distribution and characteristics in the co-pyrolysis of date palm waste and polyethylene foam: Harnessing the potential of plastics and biomass valorization

The current methods of disposing of plastic waste, such as dumping or burning, create significant ecological problems and cause irreparable damage to valuable resources. This is especially true for plastics with complex structures, like polyethylene foams (PEF). This study focuses on how the plastic composition affects the interactions, kinetics, thermodynamics, yield of pyrolysis products, and their characterization during the co-pyrolysis of date palm waste (DPW) and PEF. Co-pyrolysis experiments were conducted at three different heating rates (10, 20, and 30 °C/min) and with varying biomass ratios to plastic. The kinetic parameters were evaluated using different isoconversional techniques such as Kissinger Akahira Sunose (KAS), Vyazovkin (VZK), Ozawa Flynn Wall (OFW), and Friedman (FM). The average value of activation energy based on the Vyazovkin model is 96.31, 216.33, 232.85, 382.69, and 206.47 kJ/mol for DPW, PEF, 75PEF25DPW, 25PEF75DPW, and 50PEF50DPW, respectively. The thermodynamic results showed that the average difference between activation energy and enthalpy is 4.89, 6.02, 5.81, 5.36, and 5.61 kJ/mol for the DPW, PEF, 75PEF25DPW, 25PEF75DPW, and 50PEF50DPW, respectively. It is lowest for the DPW and highest for the PEF, whereas it is significantly lower for the mixes, indicating that the mixes consume less energy. Criado's master plot suggested that the co-pyrolysis of DPW and PEF followed D1 (one-dimensional) and D3 (three-dimensional) reaction mechanisms. Further, co-pyrolysis results from the fixed bed reactor confirmed maximum bio-oil yield (38.85 wt%) was achieved at 50PEF50DPW ratio. The results of this study suggest that combining waste date palms with PEF could be a promising option for improving the co-pyrolysis process.