Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/5106
標題: 二氧化鈦光觸媒對水溶液中小分子有機酸之去除及大腸桿菌殺菌效果之探討
Study on the removal of low molecular organic acid and disinfection effect of E.coli in aqueous solution by titanium dioxide
作者: 邵盈傑
Shao, Ying-Chieh
關鍵字: photocatalysis
光催化
low molecular orgnaic acid
E.coli
TiO2
小分子有機酸
大腸桿菌
二氧化鈦
出版社: 環境工程學系
摘要: 本研究以CVD法製備二氧化鈦光觸媒,在365nm紫外光照射下,探討小分子有機酸之去除效率,以及大腸桿菌的殺菌效果。 實驗採批次迴流法,控制變因為pH、溫度及初始濃度,在小分子有機酸部分反應物為對羥基苯甲酸及香蘭酸,以HPLC、TOC分析,在大腸桿菌部分,監測吸光度值輔以平板計數法計算菌數,然後由所得之數據,針對小分子酸光催化行為進行反應動力模式之推估。 在小分子酸背景實驗部分,結果顯示不論是揮發實驗、吸附實驗或是直接光解實驗,對後續光催化反應造成之影響皆是可忽略不計。值得注意的是兩種小分子酸在初始濃度0.1 mM、pH 5時,會有較明顯的吸附效應的產生,對降解率及礦化率的呈現即會發生影響。光催化實驗部分,對小分子酸這類消毒副產物的前驅物質的確有不錯的降解效果;在pH效應皆是隨著pH值提高而有較好的降解效率;在溫度效應,則皆是隨著溫度的提高而有較佳的降解效率;而在濃度效應方面,則兩物種皆是隨著初始濃度的降低而能獲得較佳之降解效率。礦化率部分,在不同pH、不同溫度及不同濃度下,礦化率之趨勢與降解率的趨勢皆相同,不過在pH及溫度效應中,雖然能得到不錯的降解率,但其礦化率普遍皆不佳,僅在不同濃度時,隨著濃度的降低能得到較好的礦化率。 在大腸桿菌部分,發現以365 nm時,經過4小時光催化後,大腸桿菌的殺菌效果不佳,因此更換波長為254 nm之紫外光源。在進一步之研究後,則可得到使用254 nm紫外光源時,不論是直接光解實驗或是光催化實驗,皆是在一個小時內就觀測不到有大腸桿菌的存在,顯示殺菌效果非常好。 最後,由光催化實驗針對小分子酸的數據作反應動力模式的推估,可以得到不論是對羥基苯甲酸或是香蘭酸,在不同pH值、不同溫度及不同濃度的控制條件下,皆可以符合擬一階動力模式。
This research used the TiO2 photocatalyst produced by chemical vapor deposition (CVD) method and a UV lamp with 365nm wavelength to study the removal of low molecular organic acid and disinfection effect on E.coli. The experimental equipment was a batch recycle system. The controlled parameters included pH, temperature and initial concentration of organic acid. In the part of low molecular acid, the reactants were p-hydroxybenzoic acid and vanillic acid, which determined and monitored by HPLC and TOC. In the part of E.coli, the OD was monitored and the plate count method was used to count the amount of the E.coli. Finally, the reaction kinetic model for the low molecular acid could be established by photocatalytic data. In the results of low molecular acid background experiments, the effect of volatitlity, adsorption and direct photolysis could be ignored. It is noticed that the two reactants at 0.1mM and pH5 revealed obvious adsorption effect and affected the results of photodegradation and mineralization. In the results of photocatalysis, good degradation was presented for the low molecular acid which is the disinfection by-product precursors. The degradation extent increased with the pH, temperature and decreased with reactant initial concentration. On the aspects of mineralization, the mineralization trend was the same as the photodegredation for different pH, temperature and initial concentration. But in the pH and temperature effect, although there was better photodegradation , the mineralization was worse. Only in the different concentration, there was better mineralization with the decreased reactant concentration. In the results of E.coli, it revealed bad disinfection effect of E.coli after four hours of photocatalysis when using a UV lamp with 365nm wavelength. Therefore, the wavelength of UV lamp was changed to 254nm. After the further research, there was no E.coli existence after one hour not only in the direct photolysis but also in the photocatalysis by using the UV lamp with 254nm wavelength. Finally, the photocatalytic results of the low molecular acid were used to establish the reaction kinetic model. No matter the p-hydroxybenzoic acid or the vanillic acid could be fitted by a pseudo-first-order kinetic model at different pH, temperature and initial concentration.
URI: http://hdl.handle.net/11455/5106
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