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Aspects Regarding the Ecological Neutralization of Designated Compounds PCB/PCT from Oil Transformers and Capacitors

1970; AcademicPres; Volume: 66; Issue: 2 Linguagem: Inglês

10.15835/buasvmcn-agr

2457-1385

Ion PETRIŞOR, Gilda-Diana Buzatu, Ilie Bucur,

Environmental and Industrial Safety

SUMMARY The present paper is concerning with ecological ne utralization of PCBs, extremely toxic industrial substances, used as additive to im prove dielectric proprieties of oil in industrial transformers and capacitors. PCBs were u sed, in large quantities, for a long period of time (1929 ‐ 1979) and after prohibition has lea d to the storage of huge quantities (stock of hundreds tone as in Filiasi, Dolj, Romania). Among other methods, alkaline metals treatment is one of the most efficient PCBs neutralization me thods, due to the reducing capacity of alkaline metals, thus removing chlorine atoms from polychlorobiphenyls molecules. In this present work we use metallic potassium, me tallic sodium and an alloy of both metals (in liquid state at the ambient temperature) for PCBs ecological neutralization. The work temperature of reaction media is controlled by the quantities of alkaline metal added. Intensive mixing and fine division of alkaline meta l particles accelerate the reaction. Analyses samples were prepared by 100:1 dilution of initial oil reaction final mixture with no contaminated transformer oil. Pentachloro benzene was used as retention time marker. Samples were comparatively analyzed by a gas chromatograph (GC 8 000, Fisons Instruments, Milano, Italy). The initial temperatur e of GC oven program was 180 oC, and then increased at a rate of 5 oC/minute to 280 oC. The injector and detector temperature was 160 oC, respectively 300 oC. The injection volume was 5 µl and was performed in a splitless mode. Nitrogen (Linde ‐ Romania supply) was used as carri er gas. The marker retention time is 12 minutes. In order to remain in the purpose of the w ork, we do not identify separately PCBs congeners. Instead, we consider the global disappea rance of PCBs chromatographic peaks group (retention time between 16 and 28 minutes) in the neutralized oil, as a measure of the neutralization method. All the resulted peaks show practical absence of PCBs in reaction products, referring to the sensibility of used anal ysis method (more than 0.001 ppm). Experimentally results clearly demonstrated that pr oposed direct reduction with alkaline metals method is quite effective for ecological eli mination of PCBs beginning with ambient temperature. Also, the results indicate that chlori ne is removed as a salt beginning with ambient temperature; the yield is dependent of reac tion conditions. As a whole, method is a valuable one for PCBs ecological neutralization.