Using lignin waste as additives to bitumen for the sustainability of the circular economy: A study of the interaction of mixture components

Abstract

The growing role of the circular economy, the shortage of oil, and the expansion of its application areas have led to the search for and use of alternative raw materials that can replace/supplement petroleum products. One direction is the use of lignin, which is produced during cellulose production and can be used as a component/substitute for bitumen binders. Despite significant scientific research in this area, the use of oxidized long-term storage lignin has not been practically studied. Therefore, the purpose of this work was basic research on the interaction between bitumen and lignin, which can later serve as the basis for technologies for the use of this type of waste, obtained in Ukraine and stored for long periods in landfills. The initial lignin and the resulting mixtures with bitumen were characterized using differential thermal and thermogravimetric analysis (DTA/DTG), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The results confirm that, despite structural and compositional changes induced by long-term storage, lignin actively interacts with bitumen, forming relatively stable chemical bonds. These results will also be used to develop effective technologies for the utilization of lignin waste accumulated in the Zaporizhzhia region, with direct environmental benefits.