Removal of Organic Pollutants Via Electrochemical Oxidation Near Anodes During Electrokinetic Remediation: Proof of Concept

Abstract

This study designed a practical approach of separating electrodes chambers to prove the influence of electrochemical oxidation on pyrene removal during electrokinetic (EK) remediation. The anode and cathode electrodes were arranged in two independent soil chambers, and the soil chambers were connected by salt bridges. Salt bridges electrokinetic (SBEK) remediation avoided acid–base neutralization and facilitated the intensity of the current. The results showed that 99.5% of pyrene was removed within 7 days in anodic chamber. The removal rate of pyrene was ∼99.6–99.9% at SBEK1 anode and 29.5–36.2% at SBEK1 cathode after 42 days. The changes in current, pH, and redox potential values indicated that an efficient “oxidizer” was formed in the anode chamber. Compared with conventional EK remediation, SBEK can take place under a suitable oxidizing condition because of increasing current intensity and decreasing soil pH in the anode chamber. Furthermore, SBEK with electrode polarity reversal test had better decontamination efficiency of pyrene than fixed electrodes. Removal rate of pyrene increased to 62.9% after 14 days with polarity reversal; correspondingly, the energy consumption of SBEK test was ∼13 times higher than that of the conventional EK test. The novel application of separated electrodes chambers appears to be a viable strategy for removing organic pollutants.