以Bi/TiO2進行電解高濃度有機廢水之研究

Study on the Electrolyzing of High Concentration Organic Wastewaters by Using Bi-doped TiO2

洪聖智(Sheng-Chih Hung)

指導教授 ： 黃武章

國立屏東科技大學/工學院/環境工程與科學系所/碩士(2013年)

https://doi.org/10.6346/NPUST.2013.00136

摘要

工業有機廢水常見高濃度的化學需氧量及氨氮，如能利用二氧化鈦改質後之電催化特性加以處理去除，應具工程應用潛力。本研究以甲基藍與丙酮作為高化學需氧量人工廢水選用之污染物; 氨水及苯氨作為高氨氮廢水選用之污染物。實驗利用自行合成之鉍(Bi)改質二氧化鈦(TiO2)，以10V為工作電壓，於100 mL燒杯中添加100 mL 溶液與0.2 g改質TiO2電觸媒進行電降解試驗，電解反應時間最多3小時。結果發現Bi/TiO2電降解系統對於單一甲基藍配置之中濃度(620 mg/L)化學需氧量廢水總去除率最高為73.54 %，但對於近似單一丙酮配置之高濃度化學需氧量廢水(6100 ~ 60000 mg/L)總去除率都不高( 7.18 ~ 0.75%)；在單一氨水配置之640 mg/L氨氮廢水，最高總去除率為為19 %。本研究之Bi/TiO2電降解系統適合用於中濃度化學需氧量廢水之快速處理。對於二元混合污染物的系統，我們選擇了會有氫鍵的產生污染物分子對: 第一組為500 ~ 50000 mg/L的丙酮水溶液與100 ~ 1000 mg/L的甲基藍水溶液組成之COD廢水; 第二組為100 ~ 750 mg/L 的氨水溶液100 ~ 750 mg/L的苯氨水溶液組成之氨氮廢水。在丙酮/甲基藍莫耳比分別為55.2、110.5、552.5的條件下，以0% Bi/TiO2電降解的總去除率分別為37.70 %、33.73 %、27.89 %; 以10 % Bi/TiO2電降解的總去除率分別為64.39 %、61.39 %、56.23 %; 以30 % Bi/TiO2電降解的總去除率分別為78.03 %、80.37 %、80.25 %。在丙酮/甲基藍莫耳比分別為0.036、0.18、0.36的條件下，以0 % Bi/TiO2電降解的總去除率分別為3.94 %、3.00 %、2.55 %; 以10 % Bi/TiO2電降解的總去除率分別為9.60 %、9.22 %、9.00 %; 以30 % Bi/TiO2電降解的總去除率分別為17.25 %、16.9 %、17.11 %。
在苯氨/氨水莫耳比分別為0.07、0.38、0.57的條件下，以0% Bi/TiO2電降解的總去除率分別為23.83 %、28.32 %、27.52 %; 以10 % Bi/TiO2電降解的總去除率分別為46.35 %、47.07 %、44.59 %; 以30 % Bi/TiO2電降解的總去除率分別為67.25 %、66.80 %、68.28 %。在氨水/苯氨莫耳比分別為0.52、2.6、3.9的條件下，以0 % Bi/TiO2電降解的總去除率分別為0 %、0 %、0 %; 以10 % Bi/TiO2電降解的總去除率分別為4.44 %、0 %、0 %; 以30 % Bi/TiO2電降解的總去除率分別為11.91 %、0 %、0 %。顯見溶液污染物分子間的氫鍵確實使總去除率降低。
本研究也探討鉍(Bi)改質二氧化鈦(TiO2)前後對於污染物去除機制的改變。首先我們將去除曲線分為(1)吸附作用區與(2)純TiO2電解作用區及(3)鉍電解促進作用區。對於單一污染物的系統中，甲基藍500 mg/L的水溶液隨著鉍摻雜量增加，吸附作用及鉍之電解促進作用都增加，吸附作用以30 % Bi/TiO2為最高51.59 %，而鉍之電解促進作用以30 % Bi/TiO2為最高8.14 %。而丙酮500 mg/L的水溶液，鉍之電解促進作用不明顯，最高為1.06 %，吸附作用以30%Bi/TiO2為最高16.04 %。對於氨水500 mg/L的水溶液及苯氨500mg/L的水溶液隨著鉍摻雜量增加，吸附作用增加但鉍(Bi)之電解促進作用減少，吸附作用以30 % Bi/TiO2為最高，分別為52.94 %、35.88 %。

關鍵字

二氧化鈦(TiO2) ； 鉍(Bi) ； 化學需氧量(COD) ； 氨氮(NH3-N)

並列摘要

Industrial wastewaters are usually possessed high concentrations of chemical oxygen demand (COD) and ammonia-nitrogen (NH3-N). If they can removed by electrolyzing system, then such technique could be promoted easily for scaling-up in a real plant. In this study, ethylene blue dye and acetone were selected for the model pollutants in high COD synthesized wastewaters; while ammonia and phenyl amine were selected for the model pollutants in high NH3-N synthesized wastewaters. In this study, titanium dioxide (TiO2) doped with bismuth (Bi) was synthesized homely. The working voltage was set as 10 V; 0.2 gram of Bi/TiO2 and 100 mL solution of the synthesized wastewater in 100 mL reactor was used for testing. The maximum electrolyzing time was 3 hrs.
Experimental results showed that this system has a highest removal percentage of 73.54 % for middle concentration (620 mg/L) COD wastewater prepared by single blue dye solution and 7.18 ~ 0.75% for high concentration (6100 ~ 60000 mg/L) COD wastewater prepared by near single acetone solution. The highest removal percentage of 19 % was observed in middle concentration (620 mg/L) NH3-N wastewater prepared by single ammonia solution. Therefore this system could be used for the fast treatment of middle concentration COD wastewater.
For binary pollutant mixtures, we choice the molecular pairs of ethylene blue dye-acetone and ammonia-phenyl amine, both of them possess high Hydrogen-bonding interaction. For the first experimental set of binary COD pollutant mixtures, it was made by 500 ~ 50000 mg/L of ethylene blue dye solution and 100 ~ 1000 mg/L of acetone solution. For the second experimental set of binary NH3-N pollutant mixtures, it was made by 100 ~ 750 mg/L of ammonia solution and 100 ~ 750 mg/L of phenyl amine solution. In the case of acetone/blue dye mixture, the mixing ratio of acetone/blue dye are 55.2, 110.5 and 552.5: the removal percentage of 0% Bi/TiO2 is 37.70 %, 33.73 % and 27.89 %, respectively; the removal percentage of 10% Bi/TiO2 is 64.39 %, 61.39 % and 56.23 %, respectively; the removal percentage of 30% Bi/TiO2 is 78.03 %, 80.37 % and 80.25 %, respectively. In the case of blue dye/acetone mixture, the mixing ratio of blue dye/acetone are 0.036, 0.18 and 0.36: the removal percentage of 0% Bi/TiO2 is 3.94 %, 3.00 % and 2.55 %, respectively; the removal percentage of 10% Bi/TiO2 is 9.60 %, 9.22 % and 9.00 %, respectively; the removal percentage of 30% Bi/TiO2 is 17.25 %, 16.9 % and 17.11 %, respectively.
In the case of phenyl amine/ammonia mixture, the mixing ratio of phenyl amine/ammonia are 0.07, 0.38 and 0.57: the removal percentage of 0% Bi/TiO2 is 23.83 %, 28.32 % and 27.52 %, respectively; the removal percentage of 10% Bi/TiO2 is 46.35 %, 47.07 % and 44.59 %, respectively; the removal percentage of 30% Bi/TiO2 is 67.25 %, 66.80 % and 68.28 %, respectively. In the case of ammonia/phenyl amine mixture, the mixing ratio of ammonia/phenyl amine are 0.52, 2.6 and 3.9: the removal percentage of 0% Bi/TiO2 is 0 %、0 %、0 %, respectively; the removal percentage of 10% Bi/TiO2 is 4.44 %, 0 % and 0 %, respectively; the removal percentage of 30% Bi/TiO2 is 11.91 %, 0 % and 0 %, respectively. The effect of Hydrogen-bond interaction between pollutants on the removal percentage of synthesized wastewater is significantly.
We also investigated the removal mechanism of Bi/TiO2 electrolyzing system. The removal curve has been cut into three regions: (1) adsorption process, (2) electrolysis process of pure TiO2 phase, and (3) promoted electrolysis process of Bi-doped phase. For 500 mg/L of single methylene blue polluting solution, it is observed to increase the adsorption process and the promoted electrolysis process of Bi-doped phase, the highest adsorption process is increased up to 66.44% at 30% Bi/TiO2, and the promoted electrolysis process of Bi-doped phase is observed up to 8.14% at 30% Bi/TiO2. For 500 mg/L of single acetone polluting solution, the promoted electrolysis process of Bi-doped phase is not obvious (up to 1.06%), the highest adsorption process is increased up to 16.04% at 30% Bi/TiO2. Both for the 500 mg/L of ammonia and benzene single polluting solution, the adsorption process is increased but the promoted electrolysis process of Bi-doped phase is decreased. The highest adsorption process is observed up to 52.94% and 35.88%, respectively, at 30 % Bi/TiO2.

並列關鍵字

titanium dioxide (TiO2) ； bismuth (Bi) ； chemical oxygen demand (COD) ； ammonia (NH3-N)

參考文獻

4. 行政院環境保護署，1998，環境白皮書。

31. 張齡尹，2008，應用奈米二氧化鈦及奈米碳管於開發新穎處理含苯乙烯廢水及廢氣之聚合去除系統，碩士論文，國立屏東科技大學，環境工程與科學系碩士班，屏東縣。

1. 顏名駿，2009，以固定化細胞程序進行TFT-LCD有機廢水處理，碩士論文，私立大同大學，化學工程研究所，台北市。

3. 李哲瑋，2011，利用溶膠凝膠法製備導電Ti1-x(Bi)xO2觸媒粉體及其特性研究，碩士論文，國立屏東科技大學，環境工程與科學系碩士班，屏東縣。

16. Diebold, U., Ruzycki, N., Hermanb, G. S. and Selloni A., 2003, “One step towards bridging the materials gap: surface studies of TiO2 anatase,” Catalysis Today, Vol. 85, pp. 93-100.