電觸媒技術去除水中大腸桿菌之研究

Study on the removal of Escherichia coli by Electrocatalyst technology in the water

顏如彗(Ru-Huei Yan)

指導教授 ： 章日行

朝陽科技大學/理工學院/環境工程與管理系/碩士(2014年)

摘要

在各類飲用水水質及水源上，環保署及衛生署針對大腸桿菌訂定法規標準，而一般飲用水通常使用逆滲透（Reverse Osmosis）、臭氧及紫外線殺菌，其分別具有不同缺點。本研究利用電觸媒處理技術快速去除水中之大腸桿菌，並探討不同操作條件下之最佳可行性。電觸媒技術（Electrocatalyst）為目前新穎廢水處理技術之一，其利用一外加電場提供能量於觸媒材料，進而於觸媒材料上產生具有強氧化作用之氫氧自由基。此處理技術的優點包括易破壞細胞膜、能分解有機污染物及去除色度等，所以，本研究冀望能利用此技術達到水中滅菌的效果。
本試驗之處理水為自行配製含有大腸桿菌Escherichia coli（E.coli）的自來水，實驗初步試驗，陽極板材質選用觸媒材料Titanium dioxide（TiO2）、Ruthenium dioxide（RuO2）與石墨，陰極板則選用石墨，極板間距為7 cm，操作使用電壓梯度（14.3、21.4、28.6 V cm-1），處理時間為1分鐘。試驗結果顯示，觸媒材料TiO2的滅菌率比RuO2與石墨好，在28.6 V cm-1的電壓下滅菌率高達99%。因提高電壓梯度，能不斷產生具有強烈氧化作用之氫氧自由基（Hydroxyl radicals），可與微生物細胞中的物質反應，而破壞細胞再被分解成二氧化碳和水。
以最佳操作參數下，設計另一新多極式模組進行新試驗，陽極以TiO2為觸媒材料，陰極為石墨，極板間距為1 cm，探討使用批次式與連續式試驗，設置不同極板對數，於不同電壓（10、30、60 V）操作下，試驗最佳處理狀況為：在連續式操作電壓60 V試驗下，大腸桿菌群之去除效果不論極板數量操作下，1分鐘後即可明顯表現，滅菌率可達約100%，處理後的pH及EC並未受到影響，可以確認本模組實用性，及電觸媒技術於去除水中大腸桿菌之可行性。

關鍵字

氫氧自由基 ； 二氧化釕 ； 二氧化鈦 ； 大腸桿菌 ； 電觸媒

並列摘要

Environmental Protection Department and Department of Health of regulations established Escherichia coli standards for various types of drinking water and water resources. People usually used reverse osmosis (RO), ozone and ultraviolet light to sterilize drinking water, which possessed different advantages and drawbacks. One of the most significant advantages is that electrocatalytic material under DC electricity will produce highly strong oxidation agents（i.e., hydroxyl radicals）. These oxidation agents can easily decompose the cell membrane, degrade organic pollutants and decrease color of wastewater. In this study, the electrocatalystic technology was applied to degrade Escherichia coli（E.coli）in the tap water and the effects of different operating conditions were evaluated.
The synthetic water samples with E.coli added were used in this research. Three types of materials such as graphite, Titanium dioxide（TiO2）, Ruthenium dioxide（RuO2）was served as the anode respectively and graphite was selected as the cathode for all tests. The electrode spacing is 7 cm and different voltage gradients（i.e., 14.3, 21.4, 28.6 V cm-1）was conducted, respectively, for one-minute treatment. Results showed that the sterilization rate (99%) of TiO2 catalyst materials better than that of RuO2 and graphite under voltage 28.6 V cm-1. Under such voltage gradient, the electrocatalytic system could effectively generate hydroxyl radicals（‧OH）to react and eventually destroy the cells of E.coli.
For practical application, a multiple module with TiO2 anode and graphite cathode was applied for further test. Both batch and continuous tests were conducted by using a different number of electrode plates and different electric field of 10、30 and 60 V, respectively. The best performance was the continuous mode with 60 V for 1 minute, which could remove 100% E.coli. The EC and pH maintained stably during and after the treatment. After all, this electrocatalytic module exhibits practicality and feasibility for removing E.coli in the tap water.

並列關鍵字

Ruthenium dioxide ； Titanium dioxide ； E. coli ； Electrocatalyst ； hydroxyl radicals

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