Advancing sustainable lubricating oil management: Re-refining techniques, market insights, innovative enhancements, and conversion to fuel.

Lubricating oil disposal is considered hazardous waste and has adverse effects on the environment and human health. It is crucial to implement tight measures to regulate and minimize these impacts, or explore opportunities for oil regeneration. The paper offers an extensive review of worldwide demand for lubricating oil and its market share, with a specific emphasis on the viewpoint of Bangladesh. Furthermore, the work presents a concise overview of various re-refining methods, including acid/clay and solvent extraction, and compares them based on physical and chemical attributes such as neutralization number, viscosity, and metal contents. It is also emphasized the implementation of design modifications and the integration of current and newly developed technologies like vaxon, ecohuile, etc. to enhance productivity and durability in terms of economic and environmental aspects, to increase the quality of products with a comparison in chemical composition from FTIR and GC-MS analysis of the samples that are obtained via recycling procedures. The feasibility of using spent motor oil as a fuel with similar properties to diesel is also evaluated based on the findings from tests conducted on engine performance and emission attributes. Using nanoparticles to enhance the characteristics of lubricating oil is very promising, particularly in reconditioning old motor oil, which is currently underexplored. The primary goal of the review is to assist the re-refining industries in improving their diverse range of potential uses.