Dechlorination of Polychlorinated Biphenyls in Real Waste Transformer Oil Using a Modified Household Microwave Oven in Presence of Sodium Hydroxide and Polyethylene Glycol

Abstract

This research was carried out to assess the dechlorination and decomposition of Polychlorinated biphenyls (PCBs) in the real waste transformer oil using polyethylene glycol 1000/NaOH through a modified household microwave oven. To do so, the influence of polyethylene glycol (PEG) (1.5-7.5 g) and NaOH (0.3-1.5 g) under microwave (MW) power of 500 W on the dechlorination efficiency of PCBs, existed in real waste transformer oil, was investigated. The results showed that by increasing the PEG 1000 (1.5- 7.5g) and NaOH (0.3-1.5g) amounts, the dechlorination efficiency of PCBs increased from 35 to 99.99% under MV power of 500 W for the reaction time of 6 min. The optimum amounts of PEG and NaOH were 5 g and 1 g, respectively. The results indicated that the PCBs dechlorination rate followed first-order kinetic (k = 0.019, R2 = 0.91), and more than 90% of total PCBs were dechlorinated at the first 90 seconds of the reaction. After 90 seconds, the dechlorination rate decreased. Accordingly, results showed that MW has extraordinary influence on PCBs decomposition from waste transformer oil, and the reaction time substantially decreased compared to conventional heating.