Abstract: Polychlorinated biphenyls (PCBs) are the toxic organic compounds widely and massively distributed in the environment, and have great environmental impacts. Many scientists endeavored to devise remediation techniques to effectively treat the PCBs-contaminated matrices including water, oil, sediment, and soil. This paper summarized the research progress and development trend of reductive dechlorination of PCBs by zero-valent metal. Zero-valent metal can effectively promote the reductive dechlorination of PCBs under high temperature or the existence of Pd, Pt, Ni and Cu as catalyzers. There are three possible pathways of PCBs dehalogenation by zero-valent metal. The first pathway involves the metal directly, and the reduction occurs by electron transfer from Fe⁰ surface to the PCBs. The second pathway involves Fe²⁺,which is an immediate product of corrosion in aqueous systems. Dissolved Fe²⁺ is a reductant capable of causing PCBs dehalogenation. The third athway for reductive dehalogenation by iron involves the hydrogen produced as a product of corrosion with water. In this paper, the effective, low-cost, and facile characteristics of PCBs reductive dechlorination by zero-valent metal were commented, and the further research areas were prospected.

Key words: Actinidia fruit, Bagging, Ecological effect