Electrokinetic transport of CMC-stabilized Pd/Fe nanoparticles for the remediation of PCP-contaminated soil

The electrokinetic (EK) transport of carboxymethyl cellulose (CMC)-stabilized nano Pd/Fe was evaluated for the remediation of pentachlorophenol (PCP)-contaminated soil. Results showed that O2 and low pH (< 4) could destroy the stability of CMC-stabilized nano Pd/Fe, and PCP in solution can be effectively and quantitatively dechlorinated to phenol by the CMC-stabilized nano Pd/Fe. Therefore, the CMC-stabilized nano Pd/Fe was injected into the central position between anode and cathode for the EK transport. PCP in soil column near the anode was moved toward the cathode and was dechlorinated to phenol by the nano Pd/Fe. PCP in soil column near the cathode was dechlorinated by the transported nano Pd/Fe. In a typical test, about 70% of PCP spiked was recovered with 46.6% as phenol. PCP and phenol were mostly collected in the cathodic compartment. Remarkable increase of Fe content in the cathode side of injection position proved that EK could successfully transport the CMC-stabilized nano Pd/Fe into the low-permeability soil.

► The stabilized nano Pd/Fe was destroyed at low pH and with aeration.
► Stabilized nano Pd/Fe can be electrokinetically transported in clayed soil.
► Stabilized nano Pd/Fe should be injected in central location.
► PCP-contaminated soil was successfully treated.