A facile approach for refining waste lubricant oil: A hazardous water contaminant

Oil lubricants are widely used to minimise friction and avoid corrosion. When lubricating oils get used frequently, they become contaminated with harmful heavy metals from degraded additives, PCBs (polychlorinated biphenyls) and PAHs (polyaromatic hydrocarbons). Used Lubricant Oils (ULOs) are harmful and dangerous to the environment, especially to water. Disposal or dumping on the surface may affect groundwater or sewage, causing severe environmental problems. Water cannot mix with oil; thus, it produces a thick layer of sludge in the water instead. This suffocates fish, tangles in the feathers of seabirds, prevents them from flying and dims the light that affects photosynthesis. Therefore, purification, reclamation, or recycling of used lubricating oils has become necessary. Adsorption is an ordinary, simple, affordable, and practical method for recycling used lubricant oil. Therefore, this study aims to develop facile, simple, inexpensive conducting polymer-based compositions. Polyaniline-based composites are being synthesised for the project, and their potential as an adsorbent material for recycling ULOs has been investigated. The results show the recovered oil sample was free from both solid and aromatic impurities. The densities of the recovered oil sample were reduced from 892.75 kg/m3 to 850.26, 855.95, and 852.73 kg/m3 using three adsorbents, showing the removal of dense heavy particles. In addition, the viscosity data indicate that certain contaminants were effectively eliminated after the treatment.