Electrochemical degradation of organic contaminants in soil and groundwater using boron-doped diamond electrode

Abstract

Boron-doped diamond (BDD) electrode has received growing attention because of its unique characteristics such as extremely wide potential window, inert surface with low adsorption properties, and remarkable corrosion stability. Thanks to these properties, in electrochemical advanced oxidation process (EAOP), it can produce strong oxidants such as hydroxyl radicals during water electrolysis and degrade organic pollutants with a high current efficiency, and provide a long service time compared with conventional anodes. If BDD electrode is applied to electrokinetic (EK) soil remediation process (EK-BDD process), in-situ degradation of organic pollutants could be achieved by combining electrochemical reactions on anode with electrokinetic movement of contaminants and oxidants under electric field. Moreover, it can eliminate the post-treatment of effluent and anode corrosion might be resisted. This study is aiming to develop an in-situ remediation technology that can completely degrade refractory organic pollutants in soil/groundwater using BDD electrode. The removal characteristics and efficiency were investigated in electrochemical oxidation/reduction tests with single or mixed pollutants. The feasibility of EK-BDD process was also evaluated by conducting EK tests with BDD anode for representative contaminants. For the synthesis of BDD electrode, appropriate pretreatment methods and operational conditions of HFCVD (Hot-filament chemical vapor deposition) were examined. To evaluate prepared BDD electrode, it is investigated that degradation of various organic pollutant with BDD electrode. The degradation of phenol was conducted with various conditions. Effects of current density, initial pollutant concentration, solution pH, temperature, and electrolyte concentration were investigated on the removal. The experimental data were well fitted with model equation derived theoretically. Due to the prediction of removal and current efficiency, it may be possible t...