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標題: | 水中天然有機物與濁度對外加電場薄膜處理程序之影響研究 Effects of Natural Organic Matter and Turbidity on Electrically Enhanced Membrane Filtration |
作者: | Yu-Ting Tsai 蔡宇庭 |
指導教授: | 李公哲 |
關鍵字: | 腐質酸,高嶺土,薄膜外加電場過濾程序,臨界電場,SUVA, Humic acid,Kaolin,Electric enhanced membrane process,Critical electric field strength,SUVA, |
出版年 : | 2006 |
學位: | 碩士 |
摘要: | 薄膜程序最大的問題即是薄膜積垢,許多研究指出水中天然有機物本身或其與顆粒結合是造成薄膜積垢的主因,因此本實驗配置三種腐質酸及高嶺土不同濃度配比之模擬水樣,分別為5 mg/L HA、5 mg /L HA+5 mg/L Kaolin、5 mg/L HA+50 mg/L Kaolin,進行MF薄膜外加電場過濾程序,並於不同施加壓力及電場強度操作下進行試驗,以評估高嶺土與腐植酸共溶於水中對電場過濾之影響。
本研究結果顯示水中含有濁度(本研究以高嶺土加以模擬)及腐植酸對於外加電場薄膜過濾,不論在通量之改善或腐植酸之去除均有正面效益。 再者,於未施加電場下,5 mg/L HA+50 mg/L Kaolin水樣通量衰減最為嚴重,施加壓力越大者通量衰退程度亦較大。於未施加電場下,腐植酸去除率(以DOC表示)方面,施加壓力大者去除率高,5 mg /L HA+50 mg/L Kaolin水樣也較另外二者為高。在阻力分析方面5 mg /L HA+50 mg/L Kaolin水樣的總積垢阻力Rf 為最大,但大多為可藉由純水水力清洗去除的可逆積垢。 然於外加電場下,上述三種過濾通量皆有隨電場強度之增高而越能維持的現象,但施加電場高於臨界電場強度時,此時所增加之電場未能反應在通量的增加上,顯示可能已超過一臨界穩定態;而於DOC去除率方面三種水樣的去除率皆有因施加電場強度增加而提升的趨勢,但於超過臨界電場之狀態下,對於此三種水樣之去除率的增加已屬有限,因此所施加之有效電場強度若能維持在臨界電場強度附近,將可得到較佳的操作成效。於施加壓力49 kPa下,5 mg/L HA、5 mg/L HA+5 mg/L Kaolin及5 mg/L HA+50 mg/L Kaolin三種水樣之DOC平均去除率,分別由未施加電場的4.41%、7.8%、9.48%提升至施加73.32 V/cm電場後的71.63%、78.49%、79.35%,分別約增加67%、71%、70%的去除率,DOC去除率皆有大幅增加的趨勢。阻力分析方面5 mg /L HA+50 mg/L Kaolin(69 kPa)於未外加電場增加至電場強度73.32 V/cm時,其積垢所造成的阻力Rs由佔過濾總阻力的82%降至37%,5 mg /L HA+50 mg/L Kaolin在外加電場操作下,其積垢阻力的減少相當顯著。於SUVA分析方面,三種水樣在外加電場薄膜過濾後,SUVA 值皆有明顯降低之效果,顯示外加電場的確可以提升消毒副產物之有機前質的去除效率。 The major problem in membrane process is fouling. Many studies reported that the main reason which caused fouling is NOMs or NOMs combining with particles. In this study, three various mixed solutions (5 mg /L HA, 5 mg /L HA+5 mg/L Kaolin, 5 mg/L HA+50 mg/L Kaolin) were used to simulate surface water. The effect of different ratio of humic acid (HA) to kaolin on electrically enhanced membrane process under various pressures and electric field strength were investigated. The results of this study showed that the electrically enhanced membrane process could improve the flux and rejection of HA when the solution contained turbidity (kaolin) and HA. Moreover, when electric field was not applied, 5 mg/L HA+50 mg/L Kaolin solution caused the most flux decline. The flux decline was getting worse and the HA rejection (DOC) was getting better with increase of pressure. The DOC rejection for 5 mg/L HA+50 mg/L Kaolin solution is better than that for the other two solution. Through the calculation of resistance for membrane, 5 mg/L HA+50 mg/L Kaolin solution caused the highest total fouling resistances (Rf), but most of the fouling resistances could be classified as reversible resistance in this case. When applied electric field strength was below critical electric field strength (Ec), the flux and HA rejection (DOC) increased with the augmentation of the electric field. However, further improvement could not be obtained when electric field strength exceeded Ec. By analyzing the fouling resistances, the total fouling resistences for 5 mg/L HA+50 mg/L Kaolin solution (69 kPa) reduced from 82% to 37% when the electric field strength increased from 0 to 73.32 V/cm. Under the electric field application, SUVA value decreased obviously, it showed that electrically enhanced membrane process could effectively improve the rejection of DBP precursors. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/31905 |
全文授權: | 有償授權 |
顯示於系所單位: | 環境工程學研究所 |
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