A new perspective towards in-situ cold plasma remediation of polluted sites: Direct generation of micro-discharges within contaminated medium

The in-situ treatment of solid wastes might be regarded as cost-effective and minimum environmental fingerprint solution, particularly with reference to contaminated soils, offering several benefits compared to ex-situ methods. In this short communication it is described the study of a lab-scale coaxial dielectric barrier discharge (DBD) plasma reactor simulating the in-situ soil remediation conditions for the first time. In this conceptual design, the contaminated medium is handled as a part of the electrical discharge, while the plasma discharges are produced directly within the contaminated porous medium under treatment, thus scattering reactive species directly in the air contained inside its interconnected pores. The in-situ cold plasma setup was used to remediate bauxite samples highly contaminated by oil sludge contaminants. A very high TOC removal (similar to 70%) was achieved after 30 min of plasma treatment time with the corresponding energy consumption being 0.53 kWh kg(-1). Carbon balance analysis of the exhaust gases revealed that 61% of the removed pollutant was converted to CO2, 19% was decomposed to CO, and 20% was emitted as VOCs. The scale-up of the presented in-situ cold plasma approach could lead to a promising alternative for the fast, cost-effective, and green in-situ remediation of granular porous, heavily contaminated with hydrocarbons contaminated sites. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

This study introduces a lab-scale coaxial dielectric barrier discharge (DBD) plasma reactor for in-situ remediation of contaminated soils, achieving a TOC removal rate of around 70%. The in-situ cold plasma approach shows promise as a fast, cost-effective, and environmentally-friendly method for remediation of heavily contaminated sites.