Regeneration of Natural Sorbents Contaminated with Oil Products in Coaxial and Planar Systems Using Dielectric Barrier Discharge

Abstract The paper compares the efficiency of oil products decomposition from the surface of an adsorption material, which was natural diatomite, consisting mainly of silicon oxide, using a coaxial and planar system implementing a dielectric barrier discharge. It is shown that plasma treatment of diatomite uncontaminated with oil products results in an increase in the sorption capacity, which means that in addition to the regeneration of the sorbent, its modification also occurs due to an increase in the surface activity of the sorbent. In the case of using a reactor with a coaxial arrangement of electrodes with approximately the same rate constant and rate of destruction from the surface, this reactor provides a higher sorption capacity after the treatment due to a higher access of active particles to the surface of the adsorbent in the system. Each cycle of the contaminated sorbent treatment in the reactors resulted in a decrease in its sorption capacity; however, even at the fifth regeneration cycle, the sorption capacity of the sorbent was higher than the initial capacity with both the coaxial and the planar system. Surface analysis and determination of the diatomite’s sorption properties, estimated from its specific surface area using low-temperature inert gas adsorption allowed us to construct liquid nitrogen adsorption/desorption isotherms on the diatomite surface after treatment. BET analysis of these isotherms revealed that the sorbent’s specific surface area and mesopore volume remained virtually unchanged, as before treatment. The adsorbent’s surface area also remained unchanged.