Laboratory of Hygienic Chemistry and Molecular Toxicology, Department of Biopharmaceutical Sciences, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu 501-1196, Japan.
Chemosphere. 2013 Jan;90(1):57-64. doi: 10.1016/j.chemosphere.2012.06.074. Epub 2012 Aug 31.
Polychlorinated biphenyls (PCBs) were mainly used as lubricants and coolants in electrical equipment. However, their chemical stabilities as well as hydrophobic properties caused persistent environmental pollution and damage to human health based on their bioaccumulative property. PCBs are currently targeted for worldwide elimination and should be disposed by 2028 based on the Stockholm Convention on Persistent Organic Pollutants. The conventional PCB degradation methods require high-heat, high-pressure or/and strongly basic conditions. The development of a safer and more practical method, therefore, is desired. We have reported a catalytic degradation method of PCBs based on a palladium on carbon (Pd/C)-catalyzed dechlorination in the presence of Et(3)N under ambient hydrogen pressure and temperature. In this study, we demonstrate a more practical system using magnesium metal instead of Et(3)N for the dechlorination of a variety of aromatic chlorides. The method was applicable for the complete degradation of a variety of PCB mixtures, such as Aroclor 1242, 1248, 1254 and PCBs removed from a capacitor to produce only biphenyl and magnesium chloride as the maritime component, both of which are less toxic and easily separable. Moreover, the Pd/C could be recovered and reused at least five times without any loss of catalytic activity. The present Pd/C-Mg-H(2) system is a simple, safe, inexpensive, and environmentally-benign degradation method of PCBs.
多氯联苯 (PCBs) 主要用作电气设备的润滑剂和冷却剂。然而，由于其具有生物累积性，它们的化学稳定性和疏水性特性导致了持久的环境污染和对人类健康的损害。根据《关于持久性有机污染物的斯德哥尔摩公约》，PCBs 目前被定为全球消除的目标，应在 2028 年之前进行处理。传统的 PCB 降解方法需要高温、高压或/和强碱性条件。因此，需要开发一种更安全、更实用的方法。我们已经报道了一种基于钯碳 (Pd/C) 在环境氢压和温度下在 Et(3)N 存在下催化脱氯的 PCB 催化降解方法。在这项研究中，我们使用镁金属代替 Et(3)N 展示了一种更实用的系统，用于各种芳香族氯化物的脱氯。该方法适用于各种 PCB 混合物的完全降解，例如 Aroclor 1242、1248、1254 和从电容器中去除的 PCB，只产生联苯和氯化镁作为海洋成分，两者毒性较小且易于分离。此外，Pd/C 可以至少回收和重复使用五次，而没有任何催化活性损失。目前的 Pd/C-Mg-H(2) 系统是一种简单、安全、廉价且环境友好的 PCB 降解方法。
