Estudio de la modificación de arcilla bentonita mediante activación ácida para la purificación de aceites lubricantes de automotor usados

Abstract

The present work is a study about the modification of bentonite clay by acid activation with the purpose of bleaching used motor oils. A natural bentonite obtained from Ecuador, was trated through acid activation with sulphuric acid, acetic acid and a mix of both. Also, three different concentrations from 20% to 60% were evaluated at 90°C during 5 hours. Activated clay samples were used to treat used oil with 25% of clay in volumes of 20 mL each one. The clay's characterization was carried out by infrared spectroscopy with Fourier transform (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM), in order to know the structural and morphological changes produced by the activation process. The results shown that activation using sulfuric acid and activation with the mix of both, have a similar transformation in the bentonite structure that appears in the leaching of intermediate layer cations. Analysis as TAN, TBN, FTIR and viscosity index were carried out to figure out the treated lubricant oil quality. The results showed a decrease of 80% of acidity and 29% of alkalinity. The viscosity index went from 85,0 to 110,9. Bleaching yield was determined by Uv-Vis analysis. Results showed acid activation increases to 70% bleaching power. The yield achieved with activated clay using 40% sulfuric acid was 69,5% while the efficiency using the activated clay sample using the mixture of sulfuric acid and acetic acid was 68,14%.