Investigation of Model Compounds for Disinfection by-Product Precursors by Lanthanide Ion Probe

• Main Authors: Ching-Ru Chao, 趙靜茹
• Other Authors: Shyh-Fang Kang
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/59678043554326869421

碩士 === 淡江大學 === 水資源及環境工程學系 === 90 === In this study, five model compounds of disinfection by-product precursors were used to form complexes with lanthanide ion (Terbium, Tb). Special spectroscopic characteristics of lanthanide ions make them attractive for probing fluorescence intensity of lanthanide-model compound complexes. The purpose of this research was to investigate the relationship between structures of model compounds with fluorescence intensity of complexes and to study the relationship between structures of model compounds and activated aromatic rings of nature organic material using changes of UV absorbance by chlorination. Results showed that the fluorescence intensity of Tb-model compound complexes were higher than that for Tb ions alone. For example, at excitation wavelength of 270 nm, the highest fluorescence intensity was found for Tb-isophthalic acid complex and was 49 times more than that for Tb alone, while at excitation wavelength of 320 nm, the highest fluorescence intensity was found for Tb-2,4-dihydroxybenzoic acid complex which was about 13 times more than that for Tb alone. Result also showed a local maximum of fluorescence peak for excitation wavelengths between 250 to 300 nm for all five model compounds tested, indicating model compounds receiving energy and undergoing transition to singlet excitation states, and then absorbed energy transferring from model compounds to Tb ions by intra- and inter-molecular migration when model compounds make transition back to ground state. Fluorescence intensity at excitation wavelength of 270 nm for Tb-model compounds complexes increases with increasing numbers of carboxyl functional groups in the structure of model compounds, while that at excitation wavelength of 320 nm increases with the numbers of phenolic functional groups. Binding capacity of NOM for Tb decreased after chlorination due to destruction of Tb binding sites after chlorination. The opposite effect was found for isophthalic acid which might be caused by the formation of intermediates and creation of extra binding sites after chlorination.