Adsorption Purification of Used Industrial Oil Using Natural Aluminosilicates

Abstract

The results of adsorption purification of used industrial oil in the presence of natural aluminosilicates, bentonite and mordenite, are discussed. It was found that the maximum degree of purification was achieved in the presence of mordenite and reached 61.68 % at an oil, adsorbent ratio of 2.3 at a temperature of 70 °C. The data of the structural-group analysis of the oil showed that the main share of the hydrocarbon components removed during purification is accounted for by highly condensed aromatic ones. The supposed reasons for the different adsorption activity of bentonite and mordenite samples were judged from the data of chemical, mineralogical, textural, and IR spectroscopic analysis. Based on the results of the IR spectra of mordenite samples, it was concluded that energetically active hydroxyl groups can be responsible for their increased adsorption activity. The used oil before purification is characterized by a high cyclicity of the hydrocarbons which included in the composition (aromatic hydrocarbons account for 38 % of the total), while the oil subjected to adsorption purification with mordenite (M-50) mainly becomes free of aromatic rings (the proportion of aromatic hydrocarbons decreases up to 19.6 %). This is a consequence of the high polarizability of aromatic hydrocarbons, in which, compared with other oil components, a dipole moment is easily induced under the influence of the electrostatic field of the adsorbent.