Morphological Evolution in the Co-Hydrothermal Carbonization of Polyvinyl Chloride and Empty Fruit Bunch

Hydrothermal carbonization is an efficient and environmentally friendly method for the treatment of polyvinyl chloride (PVC), enabling its clean utilization. The co-hydrothermal carbonization of polyvinyl chloride (PVC) and empty fruit bunches (EFB) was conducted under varying experimental conditions, such as temperature. Techniques including scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) were employed to investigate the morphology and formation mechanisms of spherical hydrochar. The study revealed the effects of reaction temperature and stirring power on the morphology and formation of hydrochar. It reveals the effects of reaction temperature and stirring power on the formation of hydrochar. The results demonstrated that the hydrochar featured a distinct double-layered spherical structure. The inner layer, characterized by a dense porous morphology, was primarily composed of PVC hydrochar, whereas the outer layer, formed from EFB hydrochar, exhibited a loosely porous structure. This configuration was attributed to the substantial generation of gases during the hydrolysis process. Increasing the reaction temperature facilitates the melting of PVC and the hydrolysis of EFB, thereby enhancing the sphericity and particle size of the hydrochar. Increasing the stirring power facilitated the dispersion of molten PVC droplets, leading to a reduction in the particle size of spherical hydrochar and an improvement in its sphericity. However, when the stirring power exceeded a critical threshold, demulsification occurred, resulting in an increase in particle size and a sharp decline in sphericity. This research contributes to the control of hydrochar particle size and provides theoretical support for its development and application.