The Study of the Environmental Implications of Used Lubricating Oils by a Combination of Spectrometric Analytical Techniques

Abstract

Samples of used and unused (control sample) lubricating oil were subjected to wear metal analysis using the graphite furnace atomic absorption spectrophotometry technique (Model ALPH 4) and were also analyzed for functional groups of compound types present in them using infrared spectrophotometer (Buck Model M500). Concentrations of nine metals—Cr, Mn, Fe, Ni, Cu, Zn, Cd, Mg, and Pb in the samples were determined to ascertain environmental degradation ability of the used oils. As expected, the concentrations of the metallic species were found to be higher in used oil than unused oil. Also Cu, Pb, and Cd, which are known to be toxic at excessive levels, were found to be highly enriched (E.F. > 10) in the used lubricating oils. Infrared peaks of aromatics, alkanes, aldehydes, alcohol, and esters were shown in the lubricating oils indicating that they contain hazardous organic compounds that can cause ill-health in humans and animals.

Keywords:

• atomic absorption spectrophotometry
• functional group
• infrared
• lubricating oil
• wear metal