Concurrent oxidation and reduction of pentachlorophenol by bimetallic zerovalent Pd/Fe nanoparticles in an oxic water

[Display omitted] •Concurrent oxidation and reduction contribute on degradation of PCP on Pd/Fe NPs.•The degradation of PCP on Pd/Fe nanoparticles is a surface-mediated mechanism.•The easy dechlorination of ortho-Cl on PCP results from adsorption of PCP on Pd/Fe.•Pd/Fe NPs with dissolved oxygen (DO) are a better catalytic system than without DO.•Pd/Fe NPs can apply directly to degrade polyhalogenated compounds in an oxic water. Under the oxic condition, the most effective removal of pentachlorophenol (PCP) with Pd/Fe nanoparticles (NPs) is demonstrated as compared to the anoxic condition. Concurrent oxidation and reduction of polychlorinated compounds such as PCP by zerovalent Pd/Fe were first observed. The optimal Pd content of the bimetallic NPs is only around 0.54mgg−1 Fe. Increases in both dosage of Pd/Fe NPs and temperature enhance degradation rates and efficiency. The activation energy of 29kJ/mol indicates that the degradation is a surface-mediated mechanism. The removal mechanism also includes adsorption, which explains that the dechlorination of Cl on PCP molecules at ortho and meta positions is easier than that at para position. Overall, Pd/Fe NPs can apply directly to degrade polyhalogenated compounds in water without deaeration.