Assessment of the electro-Fenton pathway for the removal of naphthalene from contaminated waters in remote regions

Highlights: • Fuel spills in remote regions require low-cost remediation technologies. • Contaminated lithosphere and hydrosphere negatively affect environmental receptors. • Electro-Fenton technology is a viable pathway to clean up such spills. • A kinetic model for the electro-Fenton reaction is presented. • Energy consumption is minimal and achievable for environmental remediation. This work investigates the effectiveness of the electro-Fenton reaction for the treatment of wastewaters contaminated with petroleum hydrocarbons. More specific attention was given to field deployment applications in remote regions, such as the sub-Antarctic, where there is a need for low-cost technologies that can aid in remediation efforts. Naphthalene, a high priority pollutant for removal within these regions, was chosen as a model contaminant and treated with inexpensive graphite electrodes to promote the electro-Fenton pathway. Results show that naphthalene can be fully removed from a near-saturated solution, 20 mg/L, in less than 3 h of treatment. The underlying removal mechanisms were identified, and a kinetic model is presented that can accurately predict treatment outcomes at varying operating conditions of applied electric currents, 0–5 mA, and iron(II) concentrations, 0–2.0 mM. Optimal operating conditions for the electro-Fenton pathway were found to be at an applied current of 5 mA and an iron(II) concentration of 0.06 mM; this resulted in a specific energy consumption of 5.6 kWhr/kg of naphthalene removed, low enough to be operated in remote regions via sustainable energy sources.