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Background: Due to concerns over the negative impacts of PCB compounds on environment and their persistence, their production, use, and import has been banned in some countries. More recently, the Chemical Treaty on Persistent Organic Pollutants (POPs) has listed PCBs among priority chemicals for eventual elimination by 2025. The aim of this study was to determine the effect of solvents on the photodegradation of askarel oils using photolysis for reducing their hazards. Materials and Methods: The photochemical reactor, used in this experimental trial, was based on photolysis through UV/ H2O2 with a 500 ml beaker and low-pressure mercury lamp with a wavelength of 254 nm. The lamp was immersed in the beaker. The temperature and PH of the samples were constantly monitored. The experiments were repeated three times. Askarel oils were analyzed by GC/ECD. Results: The means of degradation of total PCBs due to the use of lamp for ethanol solvent and isooctane were 88% and 77%, respectively. The mean degradation of total PCBs in terms of the applied solvent ratio to the oil transformer for 1:1, 2:1, and 3:1 values for ethanol and isooctane were 55%, 85%, and 88%, and 40%, 77%, and 78%, respectively. Conclusion: Photolysis of PCB compounds in the presence of ethanol solvents, isoocatnes with strong oxidants such as H2O2, indicated their degradation or reduction in oil transformers with lower energy, and no yield of toxic byproducts. There was a significant difference in the employment of ethanol solvent and isooctane in degradation of askarel oil.

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Background: Poly chlorinated biphenyls (PBCs) are the group of organic chemical materials that have a great chemical stability. These compounds are hazardous pollutants which pose various occupational and environmental problems. This study was conducted to determine the effect of microwave rays, hydrogen peroxide, Tio2 catalyst, and ethanol on the decomposition of PBCs. Materials and Methods: In this experimental study, a vessel reactor (250ml volume)that was connected with a tube connector to thecondensor system was used. A microwave oven with a fixed frequency of 2450 MHZ was used to provide microwave irradiation and ray powers used at 540, 720 and 900w. pH and temperature of the samples were continuously monitored and the experiments were repeated three times. Askarel oils were analyzed by GC-ECD. Results: The mean of total PCBS degradation at 540, 720, and 900w was 83.88±1.63, 89.27±2.44, and 95.98±0.81%, respectively. The mean of total PCBS degradation in terms of ratio to solvent with oil transformer in 1:1, 2:1, and 3:1 was 53.8±3.26, 79.04±1.24, and 95.08±1.69%, respectively. The mean of total PCBS degradation in terms of not using H2o2/Tio2 and using H2O2 (20%) and 0.05, 0.1, 0.15, and 0.2 g of Tio2 concurrently was 71.47±0.81, 87.9±2.16, 89.48±1.69, 91.7±1.24, and 93.07±3.09 %, respectively. Conclusion: Using microwave irradiation in the presence of H2O2 oxidant and Tio2 catalyst leads to the reduction of PCBS.