Reductive Dechlorination of Polychlorinated Biphenyls by Zerovalent Iron in Subcritical Water

A method for remediation of PCB-contaminated soil and sediments is described that uses zerovalent iron as the dechlorination agent and subcritical water extraction (SWE) as the transporting medium. By using 100-mesh iron powder and SWE conditions of 250 °C and 10 MPa on Aroclor 1260 for 1−8 h, the higher chlorine-substituted homologues were completely reduced to their lower-substituted counterparts. The lower-substituted congeners were subsequently near-completely dechlorinated. The initial findings indicate that this technique may be a viable method for remediation of PCB-contaminated soil and sediments.