Electrochemical Remediation of Contaminated Real Marine Sediments under very Low Electric Fields: Case Study on the Remediation of Marine Sediment from Bagnoli Bay

One of the last decade's crucial priorities is environmental healthiness and agriculture preservation. The current technologies to restore soil/sediment are poorly effective; therefore, their remedy is still challenging [1]. Direct Current Technologies (DCTs) are considered among the most practical, sustainable, cost-effective and noninvasive in situ and ex situ options. In this approach, an electric field (E) is induced through the polluted media thanks to the pplication of a direct current between two or more electrodes directly inserted or adjacent to the contaminated site. Under these conditions, different mechanisms are mainly involved: i) electromigration (flow of charged species), ii) electroosmosis (flow of pore water and contaminants), iii) electrophoresis (movement of colloids) and iv) redox reaction on the soils/sediments’ particles and/or at the electrodes, prompting the remediation of contaminated sites [2-4]. DCTs for environmental remediation include the ElectroChemical GeoOxidation technologies (ECGO), which mineralizes organics. ECGO technologies involve less energy (i.e., typical 0.0025 ≤ E ≤ 0.25 V cm− 1) than the typical Electrokinetic processes (i.e., E ≥ 1 V cm−1) without using costly processing fluids [2]. Recently, we have demonstrated that ECGO technology could be a suitable way to treat clay kaolin or marine sediments for the in-situ removal of phenolic compounds [2], saturated alkanes [3] or PAHs [4] using E values lower than 0.25 V cm-1 without the generation of secondary effluent and at low energetic consumption. In this framework, this work aims to present the results achieved for the electrochemical treatment of sandy marine sediments from Bagnoli- Coroglio Bay (Naples, Italy) using a wide range of E (0.005 ≤ E ≤ 2 V cm− 1) for 96 hours and electrodes directly in contact with the sediment. This work was focused on the removal of the TPHs and PAHs. It was observed that the organics removal efficiency strongly depends on the adopted E values. For example, a total PAHs or THPs removal efficiencies higher than 45 or 35% were reached after 96 h of treatment under 0.05 V cm−1 coupled with a low energetic consumption due to the rather E values adopted. [1] K.R. Reddy, C. Cameselle, Electro-chemical remediation technologies for polluted soils. sediments and groundwater, John Wiley & Sons,, Hoboken, New Jersey, 2009. [2] F. Proietto, A. Khalil, W. Maouch, A. Galia, O. Scialdone, Environmental Technology & Innovation 32 (2023) 103286. https://doi.org/10.1016/j.eti.2023.103286. [3] F. Proietto, P. Meli, C. Prestigiacomo, A. Galia, O. Scialdone, , Journal of Environmental Chemical Engineering 12 (2024) 111780. https://doi.org/10.1016/j.jece.2023.111780. [4] F. Proietto, F. D’Agostino, M. Bonsignore, M. Del Core, M. Sprovieri, A. Galia, O. Scialdone, Chemosphere 350 (2024) 141009. https://doi.org/10.1016/j.chemosphere.2023.141009.