DOI: https://doi.org/10.36347/sjet.2025.v13i12.003

Pages: 892-901

Driven by the dual imperatives of environmental sustainability and economic self-sufficiency, the research addresses the critical challenge of WEO management in developing economies like Nigeria. A laboratory-scale, batch-operated vacuum distillation unit was fabricated using accessible engineering principles. The experimental process involved atmospheric dehydration, vacuum distillation for separating diesel and lubricating oil fractions, and a final polishing step with thermally activated Attapulgite clay. The produced oils were rigorously characterized and compared against virgin lubricating oil and commercial diesel using standard ASTM methods, EDXRF, and FT-IR spectroscopy. The results demonstrate that this two-step process effectively removes a broad spectrum of contaminants; including water, light hydrocarbons, wear metals, and oxidation products. The re-refined base oil exhibited physicochemical properties, such as viscosity index (93.4), flash point (209°C), and total acid number (0.4 mg KOH/g), that are on par with virgin base oil and meet industry-specific quality standards. A high-quality diesel by-product was also recovered, with properties comparable to commercial diesel, enhancing the economic viability of the process. The findings confirm that vacuum distillation coupled with clay treatment is a technically effective and environmentally sound method for WEO re-refining, providing a pragmatic, scalable, and economically attractive solution for sustainable waste management in regions facing a lack of advanced refining infrastructure.