Lubricants and Additives: A Point of View

Abstract

Lubricants are used to reduce the friction between two surfaces, improving efficiency and reducing wear. The most important application of lubricants is in the automotive sector where lubes are used to avoid damages to the engines. Additives are essential components of lubricants: they are added to lube to improve its physical and chemical properties. Additives also play a key role in the reduction of environmental burden by saving important resources, avoiding leakage losses and reducing exhaust gas emissions. Some concerns have been expressed regarding the reuse and disposal of used lubricating oils due to their possible toxicity for human and ecosystems. Most ecological effects are induced by the mineral base oils because additives are normally insoluble in water. Focusing on used oils, it is possible to say that the toxicity of these products derives from their improper disposal. Heavy metals, PCBs, dioxins, and PAHs can be released into the environment as a result of lube combustion. Modern lubricants do not contain halogenated additives; hence, very small amount of halogens may be present as contaminants from chemical processing. Moreover, modern re-refining techniques, like thermal deasphaltation, reduce the environmental impact and the toxicity of the used oils that otherwise could be disposed using incorrect ways with higher environmental load.