Abstract
In this work, the recovery of base oil from lubricating oil contaminated soils was investigated using solvent extraction. Lubricating oils are discarded into the ground or landfills and this neither protects the environment nor conserves this important resource. Extraction of used lubricating oil from the contaminated soils can produce more valuable products and reduce environmental contamination. The objective of this work was to recover the base oil from clay, loam and sand oil contaminated soils through solvent extraction using hexane. The influence of particle size distribution, soil moisture and soil characteristics on base oil recovery were studied at a solvent-oil ratio of 1:2. The soils used were collected from an open field, eliminating the need for drying; hence the influence moisture content on the separation efficiency was eliminated. The soil-oil mixture was dissolved in sodium hydroxide (NaOH) solution at 40oC while agitating at 300rpm. During this stage, base oil separated from additives. A solvent was added to extract the base oil from the lubricating oil. Distillation was used to recover the solvent from the solvent-oil mixture. The highest oil recovery (85%) was obtained from sand oil while clay gave the lowest of 40%.