Study of electrochemical remediation of clay spiked with C12-C18 alkanes

To date, the management of polluted soils and sediments is challenging because they can be characterized by heterogeneous conditions, miscellaneous contaminants (organic and inorganic ones), fine grains and low-hydraulic permeability. In these cases, the current treatment methods are poorly effective. ElectroChemical Remediation Technologies (ECRTs) are considered some of the main appealing strategies for the remediation of such complex sites. The ECRTs are based on the application of a relatively low cell potential value, between two or more electrodes, inducing an electric field (E) through the polluted media, which prompts the remediation of the contaminated site. This work was focused on the study of the electrochemical remediation of kaolin artificially spiked with a miscellaneous of five alkanes (C12H26, C13H28, C14H30, C16H34, C18H38), namely C-12-C-18. Kaolin was selected as a model reproducible, low-buffering, and low-permeability clay and the mixture C-12-C-18 as a hazardous model of petrol hydrocarbon compounds. The effect of several operative conditions, including the E intensity, type of technology, presence of supporting electrolyte, was investigated. It was found that adopted low E values can simultaneously mobilize and degrade in situ the C-12-C-18 mixture and that the shorten the chain compound, the easier the remediation efficiency, R. It was shown that the usage of E of approximately 0.50 V cm(-1) allows to reach a total C-12-C-18 removal (R(C-12-C-18)) of similar to 70% after 96 h. Finally, it was demonstrated that the usage of sodium chloride improves the performances of the process: R(C-12-C-18) increased from 61 to 83% when NaCl was added.