Detection of the Adulteration of Motor Oil by Laser Induced Fluorescence Spectroscopy and Chemometric Techniques

Petroleum products are the target of fraudulent practices due to their high commercial value. The aim of this study is to provide a new analysis system to assess motor oil adulteration. For this purpose, Laser Induced Fluorescence (LIF) spectroscopy was exploited coupled with chemometric tools to detect motor oil adulteration by three types of cheap motor oils. Principal Component Analysis (PCA) was able to distinguish samples in three groups according to the type of adulterant. Besides, Partial Least Squares Regression (PLSR) was exploited to determine the percentage of adulteration. The best model was obtained with a regression coefficient of 0.96, Root Mean Square Error of Prediction (RMSEP) of 2.83, Standard Error of Prediction (SEP) of 2.83 and Bias of 0.40. The main results of this work provide new analysis system using the combination of LIF spectroscopy combined to PCA and PLS as an efficient and fast method for motor oil analysis.

Base oil recovery from waste lubricant oil by polar solvent extraction intensified by ultrasound

This paper proposes a greener approach to the intensification of base oil recovery for truck engines (32,500 km of use) using ethanol, propan-2-ol, 2-methylpropan-1-ol, and butan-1-ol as solvents for the extraction of base oil, combining mechanical stirring (220 rpm) and ultrasound (25 °C, 24 kHz, and 400 W). The results indicated that the recovery yields of the base oil, using the mechanical stirring and ultrasound (MS-US) system, for ethanol, propan-2-ol, 2-methylpropan-1-ol, and butan-1-ol were approximately 3.1, 25.6, 71.6, and 85.5%, respectively. By contrast, the recovery yields using only mechanical stirring were 8.8, 28.9, 58.9, and 76.1%, respectively. The system with pre-extraction could effectively remove Ca (85.3-93.0%), Mg (67.2-82.9%), Na (31.7-62.5%), and Zn (0.0-71.7%). Finally, the results showed a reduction of almost 100% for the concentrations of Al, Cr, Fe, and Mo in the pre-extraction system. The mechanical stirring (5 min) and ultrasound (5 min) system were able to intensify the extraction process using environmentally friendly solvents.

Composition and source identification of deposits forming in landfill gas (LFG) engines and effect of activated carbon treatment on deposit composition

Compositions of deposits forming on engines parts operated with landfill gas (LFG) were analyzed. The deposit compositions were compared before and after the installation of activated carbon system for treatment of LFG. Deposits forming on the spark plugs had significantly higher levels of calcium, chromium, and nickel in comparison to those forming on the engine heads. The LFG contained about 9.5 ± 0.4 mg/m(3) total siloxanes, majority of which were octamethylcyclotetrasiloxane (D4) (5.0 ± 0.2 mg/m(3)), decamethylcyclopentasiloxane (D5) (2.9 ± 0.1 mg/m(3)) and hexamethyldisiloxane (L2) (1.6 ± 0.1 mg/m(3)). The samples collected from the engine heads before the activated carbon treatment of LFG had significantly high levels of silicon (149,400 ± 89,900 mg/kg) as well as calcium (70,840 ± 17,750 mg/kg), sulfur (42,500 ± 11,500 mg/kg), and zinc (22,300 ± 7200 mg/kg). After the activated carbon treatment, silicon levels decreased significantly; however, deposits had higher sulfur content (104,560 ± 68,100 mg/kg) indicating that the activated carbon released some sulfur during treatment. The analyses indicate that zinc and calcium originated from the additives in the lube oil while lead, aluminum, copper, nickel, iron, chromium were due to the engine wear.