Electrochemical removal of chloride from polychlorinated biphenyls in an oil/n-butanol/HCl and an n-propanol/HCl system

We present an exploratory study that seeks to identify new routes for the treatment of transformer dielectric oils contaminated with polychlorinated biphenyls (PCBs), through the usage of direct reduction electrochemical methods, employing Pb/PbO2 electrodes. It is possible to prepare a PCB emulsion using tensoactive agents in order to perform a direct PCB reduction effectively. Nevertheless, this procedure has drawbacks. We are focusing this study towards identifying a media capable of dissolving the contaminated oil and conferring it enough conductivity to make the direct reduction of the PCBs possible or to carry out an extraction of the PCBs from the contaminated oil before the electrolysis. To reach this goal, n-butanol as a solubilization agent and n-propanol as an extraction agent added with HCl were selected. The high electrical resistance of the media does not allow a direct reduction of the PCBs. Instead, a selective electrolysis of the PCBs, once extracted from the contaminated oil at Pb/PbO2 electrodes can take place. ©The Electrochemical Society