碩士 / 國立成功大學 / 環境工程學系碩博士班 / 95 / Eutrophication is becoming a more serious problem in Taiwan due to the discharge of pollutants into rivers and reservoirs. The growth of algae may affect water quality, such as causing color and odor problems. Some species of algae may even release toxin. This kind of water is difficult to treat by conventional treatment process. Unpleasant color may still be present in the treated water.
The main purpose of this research is to study the changes in extracellular polymeric substances of algae after treatment by two oxidants, namely potassium permagnate (KMnO4) and ozone. Synthetic algal suspensions with pure culture of Chodatella sp. or Nizschia sp. was used. Several tests were done to observe those changes: Fourier transformed infrared spectroscopy (FTIR) and florescence intensity was used as qualitative and quantitative analysis of EPS, respectively. Zeta potential of the algal surface was also measured. The molecular weight (MW) of the bound EPS was determined with high performance size exclusion chromatography (HPSEC). Also, the change in aggregation of algae was observed by microscope.
Results showed that there was a positive correlation between dosage of KMnO4 and fluorescence intensity for Chodatells sp. and Nitzschia sp.. This shows that KMnO4 may stimulate the production of EPS. Similar trend was found when using low concentration of ozone as oxidant. But when ozone dosage became higher, the fluorescence intensity decreased.It is speculated that EPS may be degraded by higher concentration of ozone.
In FTIR analysis, peptide bonds were found in both Chodatell sp. and Nitzschia sp.. This shows that protein may be one of the most important components of EPS. Silicon containing functional groups (Si-O-Si, Si-O-C) were also found in Nitzschia sp..
Molecular weight of Chodatells sp. is about 6000, and about 9700 for Nitzschia sp.. After treatment with potassium permagnate and ozone, no significant change was found in the MW of their EPS.
The Chodatells sp. became more aggregate when the dosage of KMnO4 increased. When treating with ozone, aggregation was only observed when ozone concentration was higher than 2 mg/L. For Nitzschia sp., the aggregation phenomenon was not obvious after treating with KMnO4 and ozone.
| Identifer | oai:union.ndltd.org:TW/095NCKU5515039 |
| Date | January 2007 |
| Creators | Chun-Hong Wang, 王淳弘 |
| Contributors | Hsuan-Hsien Yeh, 葉宣顯 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 95 |
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