| Summary: | 博士 === 國立清華大學 === 生醫工程與環境科學系 === 95 === This study aims to measure MTBE and volatile organics (VOCs) in the ambient air and using ionizing radiation to degrade MTBE in water. Canister sampling with GC/MS analyzed MTBE and VOCs in the ambient air around gasoline stations during rush hours and assessed their impact on human health. Results from this study clearly indicate that methyl tert-butyl ether (MTBE), toluene,ethyne , isobutene, and n- butane are the major VOCs. Moreover, the concentrations of these compounds in the ambient air near gasoline stations are remarkably higher than those sampled on traffic roads, revealing that these compounds are mainly released from gasoline stations. The concentrations of MTBE and VOCs near the gasoline stations without vapor recovery systems are about 20 and 7.3 times higher than those around the gasoline stations having the recovery systems. The risk of MTBE to the reproductive systems at the sites without vapor recovery system was higher than the normal acceptable values.
The radiolytic degradation of MTBE in aqueous solution was studied under different conditions. Moreover, in this experiment, using Headspace-SPME coupling GC/FID determine the degradative products. Results show that complete degradation of MTBE can be achieved within 5 min of irradiation at 59.7Gy/min. Tert-butyl formate (TBF), tert-butyl alcohol (TBA), acetone, methyl acetate (MA) were found to be the primary intermediates of the degradation reaction with yields of 47%, 11%, 6.4% and 9.1%, respectively. However, the removal of MTBE is significantly decreased with increasing concentration of benzene. In addition, the presence of cupric ions appears to reduce degradation of TBF, while the removal of MTBE is not significantly affected.
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