Remediation of pyrene-contaminated soil by active species generated from flat-plate dielectric barrier discharge

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 296; pp. 356 - 365
• Main Authors: Mu, Ruiwen, Liu, Yanan, Li, Rui, Xue, Gang, Ognier, Stéphanie
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.07.2016
• Subjects: Active species; Degradation; Dielectric barrier discharge; Electric potential; Electrodes; Optical Emission Spectrometer; Pyrene; Pyrenes; Soil (material); Soil remediation; Voltage; Soil remediation; Pyrene; Active species; Dielectric barrier discharge; Optical Emission Spectrometer
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2016.03.106

[Display omitted] •The active species containing oxygen and nitrogen both contributed to the pyrene removal.•DBD technique was proved to be able to remediate pyrene polluted soil in a broad pH range.•Pyrene degradation mechanism was explored based on GC–MS, FT-IR and OES analysis. In this study, soil polluted with pyrene was remediated using a dielectric barrier discharge (DBD) plasma reactor at atmospheric pressure. Influencing factors, including treatment time, discharge voltage, electrode gap, gas flow rate, initial pyrene concentration, and pH of the soil, were studied. Experimental results showed that pyrene degradation efficiency was influenced on a small scale by soil pH: the pyrene removal rate reached 76% in alkaline condition (pH of 11.69), i.e., 8% higher than in neutral conditions (pH of 7.76) and 13.7% higher than in acidic conditions (pH of 5.67). The removal of pyrene increased as the applied voltage increased and the electrode gap decreased. The optimal airflow rate was 1.0L/min. The more pyrene that was coated on soil particles the higher was the energy efficiency, but the plasma penetrating pyrene layers faded by approximately 25% when the layers doubled. Optical Emission Spectrometer (OES), FT-IR and GC–MS data indicated that the excited atomic nitrogen, atomic oxygen and NOx were abundant in the plasma, and that the active species containing oxygen and nitrogen both contributed to the decomposition of pollutants. The possible pyrene degradation pathway was suggested. The experimental results showed that the DBD technique was able to effectively degrade pyrene over a broad pH range.