| During the extraction of PCBs from soils, co-contaminants such as transformer oil (TO) and other hydrocarbons contaminant also get extracted. These co-contaminants may interfere in the degradation of PCBs in the extractant. In this thesis, effects of co-contaminants on the degradation of PCBs (Aroclor 1254) as well as the degradation of the co-contaminants have been investigated.;Two new gas chromatographic methods were developed to analyse and characterize transformer oil, a major co-contaminant in PCB impacted soils. Use of hydrogen peroxide to degrade transformer oil was also investigated. Further, 1H and 13C NMR spectroscopic techniques were used to analyse the degradation of transformer oil by hydrogen peroxide. H2O 2 concentration of 30% was observed to be better, even though the overall degradation of transformer oil was limited. The total amount of TO degradation increased with TO content in the soil and approached a limiting value. From 1H and 13C NMR spectroscopic studies, it was concluded that aromatics were most easily oxidized and paraffinic and naphthenic compositions changed upon application of H2O2.;Some adverse effects of the co-contaminant were noted on the degradation of Aroclor 1254 when treated with H2O2. Higher H 2O2 concentration was more effective in degrading PCBs.;Limited adverse effects of the co-contaminant were observed on the 254 nm UV dechlorination of PCBs (Aroclor 1254) and its major congeners. Congeners with higher degrees of chlorination were found to dechlorinate faster than lower chlorinated congeners in the mixture. Five-minute irradiation experiments revealed that pseudo first order kinetics described the UV dechlorination of Aroclor 1254. The rate constant was determined to be 4.3 x10 -3 s-1 when there was no TO, but when 200 mg/L or more TO was introduced, the rate constants decreased by about 15%. The transformer oil did not degrade in the UV environment. |
