| Summary: | 碩士 === 國立中興大學 === 環境工程學系所 === 99 === Polychlorinated biphenyls (PCBs) are a family of biphenyl molecule compounds which pick of several chlorine atoms. Because of their excellent thermal conductivity, electrical insulation, PCBs are used extensively for the industrial manufacture of transformer boxes, capacitors, paints and inks. Because of the high lipophilicity, and the physical and chemical stability, PCBs is easy to accumulate in the soil, sediment, and even through the food chain accumulate in higher organisms as well as in the human body. And PCBs are also highly resistant to degradation in nature and metabolize slowly in organisms. If they enter into human body could lead to skin disease, and damage to the nervous system and immune system, also carcinogenic. For example, to one of Taiwan''s most polluted Er-Ren river, the sediment in the Taiwan''s most polluted Er-Ren river contain high levels of PCBs above the regulatory limit and in urgent to regulate. There are two biologically processes which could degrade PCBs effective in sediment: anaerobic reductive dechlorination and aerobic oxidative degradation. These processes have been used to for several years, but the biodegradation time was needed. However, the sediment in the Er-Ren river also contain high levels of heavy metal which could reduction the biodegradation of PCBs. Based on the above characteristics of pollution, this study will try to add nanoemulsion to increase the efficiency of biodegradation in simulation sediment content Aroclor 1242 (one commodity of PCBs), and also add magnetite nanoparticle which be report could adsorb heavy metal to identify the influence for biodegradation.
The result show that the efficiency of aerobic biodegradation is better than anaerobic biodegradation without adding nanoemulsion and magnetite nanoparticle. When adding few amount (0.1%) of nanoemulsion into the sediment contented yeast extract under the anaerobic condition could increase the efficiency of anaerobic reductive dechlorination, but will product a little of gas volume with adding high amount of nanoemulsion (10%). Adding few amount (20 mg L-1) of magnetite nanoparticle also could increase the efficiency of anaerobic reductive dechlorination. However, adding nanoemulsion will reduce the efficiency of aerobic oxidative degradation, and magnetite nanoparticle will not change the efficiency. Furthermore, under the same additional amount of nanoemulsion and magnetite nanoparticle the best condition to degrade Aroclor 1242 is standing environment.
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