Atmospheric pressure dielectric barrier discharge for the remediation of soil contaminated by organic pollutants

Abstract

The remediation of soil, contaminated by organic pollutants, in a cylinder-to-plane dielectric barrier discharge reactor at atmospheric air pressure was reported. Two model organic pollutants were selected; a solid pollutant (2,6-dichloropyridine) and a liquid pollutant (n-dodecane). The effects of the contaminant's initial concentration and state, the energy consumption, and the soil type on the pollutant removal efficiency were investigated. To that scope, various contaminated samples of both quartz sand and loamy sandy soil were treated by plasma for various treatment times and initial 2,6-dichloropyridine/ n-dodecane concentrations. The results revealed that (1) the removal efficiency of 2,6-dichloropyridine was higher compared to that of n-dodecane at a given plasma treatment time and (2) the removal efficiency increased with the energy density increasing, but decreased as the soil heterogeneity, organic matter and pollutant concentration were enhanced. The main removal mechanism proposed is the evaporation of pollutant molecules coupled with their oxidation by plasma species in the gas and solid/liquid phase.

Applications of Plasma-Liquid Systems: A Review

“…Soil remediation using plasma technology was also examined in some research papers [269,279,280,281]. In a study by Wang et al [282], p-nitrophenol pollution was decomposed faster in moist soil as compared to dry soil when using a DC air pulsed discharge.…”

Modeling of dielectric barrier discharge (DBD) plasma reactor for soil remediation

“…After testing the methodology with the simple case of having Argon as the main gas in the discharge gap, the more complex case of containing dry air was investigated. Air is the main gas that is used by collaborators in the present DBD experimental apparatus [59], and the present theoretical model reconstructs the conditions of this experimental setup. Numerous recent studies investigated plasma discharges taking place in atmospheric air conditions, such as for the study of the lightning effect or the discharges generated through friction between airplanes and the air molecules [60].…”

“…In the present study, the discharge gap is filled with air and the microscopic timescale problem is described by a model of 45 key plasma reactions [47]. These 45 reactions, which are only part of possible interactions, are responsible for the plasma generation, and for the creation of highly reactive molecules, such as atomic oxygen, excited atomic oxygen, atomic nitrogen, excited N2 molecules, O3, OH, NO, and NO2, which participate in the oxidation reaction of NAPL compounds [59].…”

“…Chapter 4: Thermal and plasma transport investigation in DBD reactor 60The main contribution of this work is the combined simulation of plasma and transport phenomena, which evolve inside the reactor at different time scales. In the micro-timescale [59], the simulation predicts the active species concentrations which influence NALP removal from the soil and the intensity of the electric field. This electric field is subsequently converted into thermal energy and determines the temperature range that the reactor can achieve.…”

“…Advanced Oxidized Processes (AOP) have been developed steadily the last few years, to overcome the difficulties that other technologies could not address [99]. A very promising AOP is plasma discharge, as it creates a wide range of oxidized species able to interact with and decompose a plethora of pollutants [28,31,59,76]. In this study, a model of a DBD reactor is developed to study the key features and mechanisms of cold plasma technologies used for soil remediation, in correlation with relevant experimental studies [33].…”