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1B+C Abiotic Transformation + Biodegradation (MO9/13) Photodechlorination of PCBs in Dielectric Fluids Using UV Radiation. Manzano, Manuel1, Perales, José1, Sales, Diego1, Quiroga, José1, 1 Dpt. Chemical Engineering and Environmental Technologies, Cadiz University. Poligono Rio San Pedro S/N, Puerto Real, Cádiz, Spain ABSTRACT- Although several decades have passed since the manufacturers of PCBs stopped their production, there are currently still in existence a large number of transformers containing this type of fluid; this represents the largest volume still in use of material contaminated by PCBs. Incineration is the most commonly used technology for disposing of wastes with high concentrations of PCBs, particularly dielectric oils, and this achieves an elimination of almost 100%. But in spite of this, incineration also presents environmental risks (dioxins and benzofurans) and is limited by the high costs of handling, transport and elimination of the final contaminated material. The present study describes the effect of the operating variables in the photolysis of dielectric fluids contaminated by polychlorinated biphenyls (PCBs) in alkaline isopropanol. Direct photolysis (ultraviolet light at 254 nm) of dielectric oils dissolved in alkaline isopropanol lead to 92% removal of PCBs in 60 minutes.The mechanism observed was again that of reductive dechlorination, with stoicheiometric release of chloride, and the accumulation of biphenyl, quaterphenyl and condensation products of biphenyl with isopropanol. Key words: PCBs, photodegradation, Transformer oil |
