废弃电容器油中多氯联苯的亚临界水还原脱氯

Sub-critical Water Declorination of Polychlorinated Biphenyls in Waste Capacitor Oil

电容器油中的多氯联苯（PCBs）含有从二氯到五氯同族元素的多种同系物,对环境和人类健康具有潜在风险。通过化学还原合成纳米级零价铁（n-ZVI）粒子,并将其应用于在亚临界水中对多氯联苯的脱氯。合成的纳米铁颗粒的粒径在20~100 nm之间,比表面积34.1 m2/g。在330℃的亚临界水中处理1 h,纳米铁颗粒脱氯率超过40%,而铁粉脱氯率只有不到10%。纳米铁颗粒脱氯产物主要是苯基和低氯代联苯,而铁粉脱氯产物中仅能检测到少量的低氯代联苯。因此,在亚临界水通过离解提供氢源的条件下,纳米铁具有较铁粉更好的脱氯效果。

Polychlorinated biphenyls （PCBs） in capacitor oil consist of different homologues from di- to penta-chlorinated congeners and pose potential risks to ecological environment and human being. Nanoscale zerovalent iron （n-ZVI） particles synthesized by chemical reduction were applied for dechlorination of PCBs in subcritical water. The BET surface areas of the synthesized nanoscale iron particles are 34.1 m2/g with the size of 20-100 nm. The dechlorination efficiency for n-ZVI and micrometer iron powders were 40% and 10% respectively when treatment was performed at 330℃ for 1h. Phenyls and lower chlorinated biphenyls were present as the main reaction products in the case of n-ZVI whereas only small amount of lower chlorinated biphenyls were detected when microscale iron powder was used as electro donor. Accordingly, n-ZVI possessed more excellent declorination performance than that of iron powders in the presence of hydrogen donors from dissociation of water under subcritical state.