Study on Photolysis Pathways of PCBs by UV Irradiation in Alkaline 2-Propanol.

Photodechlorination Pathways of Non-Ortho Substituted PCBs by Ultraviolet Irradiation in Alkaline 2-Propanol

“…The fact that the mass balance became imbalanced with the proceeding of the photochemical process suggested the presence of other reactions. The decomposition of BP plays an important role in this imbalance according to the previous report (Yao et al 1996) which noted that BP can also be decomposed effectively under the same experimental conditions. Moreover, the observation that all the test solutions changed from colorless to yellow during the photolyses suggested the formation of polymeric products (Hutzinger et al 1974).…”

“…The difference in wavelength of UV source is thought to be another important factor for the different results in addition to the influence of reaction solvents. It is worth noting that 90 % of the irradiation emitted by low pressure mercury lamp is at 254 nm which corresponds to those of the absorption peaks of many PCBs (Yao et al 1997) including all the nonortho substituted congeners in UV region. Furthermore, this wavelength is of considerably higher energy than 300 nm.…”

“…Furthermore, this wavelength is of considerably higher energy than 300 nm. Previous study has indicated that the photolysis rate of 2,4,4'-TriCB in alkaline 2-propanol increased when the UV source was changed from high pressure mercury lamp ( λ max =365~366 nm) to low pressure mercury lamp (Yao 1995).…”