REMOVAL OF CONTAMINANTS IN USED LUBRICATING OIL WITH CHEMICAL ACTIVATED CARBONS FROM PALM KERNEL AND COCONUT SHELLS

This research work examined the heavy metals contaminants and physico-chemical parameters of virgin and used lubricating oils using Atomic Adsorption Spectrometer for copper, cadmium, zinc, lead, magnesium, iron and chromium elements using various ASTM D methods. The results obtained shows that there were significant differences in the virgin and used lubricating oils. Comparative studies of the physicochemical properties of chemically activated carbon from palm kernel (PKS) and coconut (CNS) shells wereinvestigated. From the results obtained, the chemically activated carbon prepared from palm kernel and coconut shells showed good physicochemical properties and adsorption capacity.For instance palm kernel shells were able to reduces the following metals Zinc, 28.7%; Cadmium, 75.1%; Chromium, 67.3% and Magnesium, 97.5% respectively. In the case of coconut shells the reduction were as follows, Zinc, 64.9%; Cadmium, 96.1%; Magnesium, 91.65% and 0.6% increase in Chromium. It was observed that the coconut shell activated carbon was effective in the removal of lead (Pb), 60.50% metals while palm kernel shell could not but increase it concentration by 59.2%However, coconut shell with BET surface area of 1177.520 (m2/g) and pH 7.5, performed better as an adsorbent than palm kernel shell with BET surface area of 717.142(m2/g) and pH 8.7 respectively. Also, coconut shell haveaspecific gravity of 1.42 and moisture content of 19.7% compared to palm kernel shell with the specific gravity of 1.61 and moisture content of 20.4% respectively. In contrast,the activated carbons produced from palm kernel and coconut shells are not suitable for the removal of both copper and iron metals. The fit of this isotherm model to the equilibrium adsorption data were determined, using the linear coefficient of determination (R2). The following R2 values were obtained; Copper (0.8185), Cadmium (0.8347), Lead (0.9349), Chromium (0.9378), Iron (0.9927), Zinc (0.9953), and Magnesium (0.9997) respectively. The results obtained revealed that the Langmuir model shows a better fit due to the high coefficient of determination (R2≈ 1). The recovered oil could be used again.