Nanoremediation Coupled to Electrokinetics for PCB Removal from Soil

Polychlorinated biphenyls (PCB) are persistent organic pollutants (POP) that accumulate in soils and sediments. Currently, there is a need to develop new, sustainable, and cost-effective solutions for the remediation of PCB-contaminated soils. Zero valent iron nanoparticles (nZVI) were considered promising for the remediation of PCB-contaminated soils and groundwater.

However, critical issues related to their limited mobility remain unsolved. Direct current can be used to enhance the nanoparticles transport, based on the same principles of electrokinetic remediation (EKR). This work is a literature survey integrating the experimental work made for the electroremediation of PCB-contaminated soil, coupling electrokinetics with nZVI, starting from the tests with stabilized bimetallic Fe/Pd nanoparticles and including the comparison between the traditional three-compartment EK setup and the more recent two-compartment electrodialytic (ED) setup.

The experiments with EK and Fe/Pd nanoparticles were not encouraging for scale-up of the process, with only 20 % PCB removal. The electrodialytic setup showed best removals (>75 % in real contaminated soils) and showed several advantages, such as a higher PCB dechlorination in contaminated soil, in a shorter time, with lower nZVI consumption, a uniform distribution of nZVI in soil, and with the use of half of the voltage gradient when compared with the traditional EK setup.