Photocatalytic Degradation of Polychlorinated biphenyls using TiOィイD22ィエD2.

Polychlorinated biphenyls (PCBs) are a class of 209 discrete chemicals, called congeners，其中10个chlorine atoms are substituted to biphenyl. Their chemical and physicalstability and their electrical insulating properties led to the commercial utility of pc . theirstability have been responsible for the PCB environmental contamination problem.We conductedthe photocatalytic degradations of polychlorinated biphenyls ina plate-type batch recyclephotoreactor using TiO D22 D2O thin film were experimentally examined in acetonitrile/H D22 D2Osystem. The concentrations of higher chlorinated biphenyls, hexa-, hepta- and octa-CBs，decreased simply with irradiation time in this system，但that of lower chlorinated biphenylstetra- and pent-CBs，increased for one hour and then decreased slowly.这是suggested that some serial reactions fromhigher chlorinated biphenyls to lower substances were occurred and additional PCBs werecreated/decomposed in this system. in addition，the dechlorination rate of total PCBs of tetra- through octa-CBs was approximately 35% after 12hours of irradiation in providing the oxygen gas.Photoatalytic degradations of polychlorinateddibenzo-p-dioxins （PCDDs）和dibenzo furans (PCDFs) are experimentally examined in this system. Theconcentration of higher chlorinated H7CDDs and P5CDDs decreased simply with irradiation time，but those of lower dioxins, P5CDDs and T4CDDs，decreased slowly. PCDDs and PCDFs photolyzed 79% and the dechlorination rate of他们76% after24小时in this photoreactor irradiated by 400w high-pressure mercury lamp。

Polychlorinated biphenyls (PCBs) are a class of 209 discrete chemicals, called congeners, in which one to ten chlorine atoms are substituted to biphenyl. Their chemical and physical stability and their electrical insulating properties led to the commercial utility of PCBs. Their stability have also been responsible for the PCB environmental contamination problem.We conducted the photocatalytic degradations of polychlorinated biphenyls in a plate-type batch recycle photoreactor using TiOィイD22ィエD2 thin film were experimentally examined in acetonitrile/HィイD22ィエD2O system. The concentrations of higher chlorinated biphenyls, hexa-, hepta- and octa-CBs, decreased simply with irradiation time in this system, but that of lower chlorinated biphenyls, tetra- and pent-CBs, increased for one hour and then decreased slowly. It was suggested that some serial reactions from higher chlorinated biphenyls to lower substances were occurred and additional PCBs were created/decomposed in this system. In addition, the dechlorination rate of total PCBs of tetra- through octa-CBs was approximately 35% after 12 hours of irradiation in providing the oxygen gas.Photoatalytic degradations of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzo furans (PCDFs) are experimentally examined in this system. The concentration of higher chlorinated H7CDDs and P5CDDs decreased simply with irradiation time, but those of lower dioxins, P5CDDs and T4CDDs, decreased slowly. PCDDs and PCDFs photolyzed 79% and the dechlorination rate of them were 76% after 24 hours in this photoreactor irradiated by 400W high-pressure mercury lamp.