In-Situ Generation of Active Oxidants in Permeable Reactive Barriers

Abstract

The in-situ chemical oxidation (ISCO) is an effective technology for the remediation of organic contaminated groundwater. However, the requirement of adding oxidants, e.g. persulfate or H₂O₂, externally obviously reduces the economical efficiency of the overall treatment process. The method of in-situ generation of oxidants can avoid the disadvantage of conventional ISCO. Herein, our study indicates that the active chlorine can be effectively produced in a permeable reactive barrier (PRB) reactor, i.e. PRB-type two-compartment electrochemical device under the electric field. COD, i.e. chemical oxygen demand, as an indicator of organic pollutants in water was degraded by the in-situ electrogenerated active chlorine through the electrolysis of NaCl solution. The amount of COD removed in the anode chamber was 104 mg/L after operating the two-compartment device at 7.0 V for 12 h under the given working conditions, and COD detected in the cathode chamber was near zero, meaning all COD is removable in effluent. The results show that the in-situ electrogeneration of oxidants technology can provide a promising option for the treatment of groundwater organic pollutants.