The recycling of spent lubricating oil would reduce the environmental concerns associated with its indiscriminate disposal. Since temperature influences the properties of lubricating oil, this study investigated the effect of temperature on the properties and metals composition of used lubricating oil using simple recycling techniques. The spent lubricating oil after pyrolysis yielded 79.1 % liquid fraction, 18.2 % gaseous fraction and 2.7% solid fraction or char. The properties and composition of the pyrolysis oil were determined using the Gas Chromatography Mass Spectrophotometer (GCMS), this shows that the major composition of the refined oil is 34.037 % Octamethyl- Cyclotetrasiloxane (C8H24O4Si4). Results indicated that since the properties of viscosity, pour point and metals composition in the pyrolysis oil were improved upon at a high temperature of 420℃, waste or spent oil is a viable feedstock for lubricant production. Keywords: lubricating oil; pyrolysis; fuel properties; temperature; spent oil.

The current investigation emphasizes preparing low-cost carbon-based zirconium impregnated heterogeneous catalysts from wood dust to produce biodiesel from waste vegetable oil (WVO). Response Surface Methodology via Central Composite Design (RSM-CCD) optimized the biodiesel production process. The physico-chemical properties of waste vegetable methyl ester were determined following the American Standard Testing of Materials (ASTM). The optimum conditions were observed to be 8:1 methanol/oil ratio, 5 wt% catalyst loading, 55°C temperature, and 3 h reaction time. The corresponding response was observed to be 98.39%. The catalyst morphology and elemental composition were determined using Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray (EDX), respectively. The experimental analysis confirmed that the synthesized catalyst from wood dust under optimized conditions can transesterify WVO into biodiesel.