| 研究生: |
陳敏華 Chen, Min-Hua |
|---|---|
| 論文名稱: |
研究三氯乙烯電化學行為
與其微加工感測器之製備 On the electrochemical behaviors and the microfabricated sensor of trichloroethylene |
| 指導教授: |
周澤川
Chou, Tse-Chuan |
| 學位類別: |
博士 Doctor |
| 系所名稱: |
工學院 - 化學工程學系 Department of Chemical Engineering |
| 論文出版年: | 2004 |
| 畢業學年度: | 92 |
| 語文別: | 中文 |
| 論文頁數: | 262 |
| 中文關鍵詞: | 感測器 、電化學 、三氯乙烯 、微加工 |
| 外文關鍵詞: | sensor, microfabricated, trichloroethylene, electrochemistry |
| 相關次數: | 點閱:47 下載:2 |
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三氯乙烯是工業上一種常用的有機溶劑及去污劑,但是它亦是土壤及地下水中污染的來源。根據醫學的研究指出,三氯乙烯是一種具有致癌性的物質。因此,如何在廢水中監控三氯乙烯濃度是項很重要的指標。本研究中,先探討三氯乙烯在鉛及電鍍鉛電極的電化學還原反應行為,再依據所得之結果設計具有感測性能佳、靈敏度高、應答時間快、重覆使用性次數多及穩定性長的三氯乙烯感測器。
在有機電解液系統中,以電聚合的方法可以合成含有共軛性質的聚氯乙炔,並在紫外光-可見光譜有一最大吸收峰在波長315nm,核磁共振光譜及氣相層析圖譜顯示電解後主要產物為氯乙炔,差式掃描熱量分析法得到相變化溫度在325 ˚C。
以鉛片為工作電極感測三氯乙烯,工作電極最佳的製備條件為:1.0 M HNO3水溶液前處理30分鐘;三氯乙烯最佳感測條件為:有機電解質濃度0.025 M TBAT,感測電位-2.10 V (vs. Ag/Ag+ with 0.1 M TBAP in AN),攪拌速率250 rpm。在此條件下,三氯乙烯感測器之靈敏度為7.15 μA/cm2-ppm,應答時間10秒,且電極壽命至少四個月。另外,在此研究偵測範圍內,即三氯乙烯濃度為50至250 ppm間,可以得到三氯乙烯濃度(CL)與其感測應答電流(id)之關係為id=7.15CL,及在質傳控制下的反應速率常數為4.86810-3 (cm-s)-1。
以電鍍鉛修飾碳片為工作電極感測三氯乙烯,工作電極最佳的製備條件為:電鍍電流密度10 mA/cm2,電鍍溫度25 ˚C及電鍍時間2小時;三氯乙烯最佳感測條件為:有機電解質濃度0.01 M TBAT,感測電位-2.10 V (vs. Ag/Ag+ with 0.1 M TBAP in AN),攪拌速率100 rpm。在此條件下,三氯乙烯感測器之靈敏度為7.06 μA/cm2-ppm,應答時間15秒,且電極壽命至少二個月。另外,在此研究偵測範圍內,即三氯乙烯濃度為100至700 ppm間,可以得到三氯乙烯濃度(CL)與其感測應答電流(id)之關係為id=7.06CL,及在質傳控制下的反應速率常數為4.8110-3 (cm-s)-1。
以電鍍鉛修飾鉛箔為工作電極感測三氯乙烯,工作電極最佳的製備條件為:0.1 M HNO3水溶液前處理60分鐘,電鍍電流密度20 mA/cm2,電鍍溫度30 ˚C及電鍍時間2小時;三氯乙烯最佳感測條件為:有機電解質濃度0.01 M TBAT,感測電位-2.10 V (vs. Ag/Ag+ with 0.1 M TBAP in AN),攪拌速率155 rpm。在此條件下,三氯乙烯感測器之靈敏度為1.06 μA/cm2-ppm,應答時間20秒,且電極壽命至少二個月。另外,在此研究偵測範圍內,即三氯乙烯濃度為50至700 ppm間,可以得到三氯乙烯濃度(CL)與其感測應答電流(id)之關係為id=1.06CL,及在質傳控制下的反應速率常數為7.21710-4 (cm-s)-1。
以電鍍鉛修飾Pt-Ti薄膜為工作電極感測三氯乙烯,Pt-Ti薄膜基材的濺鍍條件為:310-3 Torr的濺鍍壓力,20分鐘的濺鍍時間及30 Watt的濺鍍功率;工作電極最佳的製備條件為:電鍍電流密度18.75 mA/cm2,電鍍時間2小時在室溫下;三氯乙烯最佳感測條件為:0.1 M TBAT有機電解質溶液,感測電位-2.10 V (vs. Ag/Ag+ with 0.1 M TBAP in AN),攪拌速率為250 rpm。此條件下,三氯乙烯感測器之靈敏度為2.86 μA/cm2-ppm,應答時間為15秒,重覆使用性至少15次及電極壽命至少六個月。另外,在此研究偵測範圍內,即三氯乙烯濃度為100至700 ppm間,可以得到三氯乙烯濃度(CL)與其感測應答電流(id)之關係為id=2.86CL,及在質傳控制下的反應速率常數為2.43410-3 (cm-s)-1。
由以上所有的實驗結果得知,當使用電鍍鉛修飾Pt-Ti薄膜電極於感測三氯乙烯時,皆具有良好的感測性能,不論在靈敏度、應答時間、電極重覆使用性與電極穩定度上均可得到良好的感測結果。除此之外,應用此電極對三氯乙烯感測器的設計是最具實用性的,因為它可以配合微加工的技術將整個感測器微小化。因此,在未來商業化產品的應用中,以電鍍鉛修飾Pt-Ti薄膜電極是最具有發展潛力。
Trichloroethylene (TCE) is a widely used organic solvent and degreasing agent in industry. However, the contamination of soil and groundwater with persistent organic pollutants is a matter of increasing concern such as TCE. There are many investigations implying the TCE is a carcinogenic material which causes serious health problems. Furthermore, how to control the concentration of TCE is a very important goal. In this study, the electrochemical reduction behaviors of TCE by using a Pb and an electrodeposited Pb modified electrodes in organic electrolyte were developed. Based on the data, a new amperometric TCE sensor can be designed with high performance, good sensitivity, short response time, nice reusability and long stability to monitor the concentration of TCE.
A novel conjugated polyacetylene chloride containing a chloric side chain which is synthesized from the TCE with an organic electrolyte by electropolymerization method. UV-Vis spectrum of the monomer shows an absorption maximum (λmax) around 315 nm due to the π-conjugation which exists in the monomer. The 1H NMR and GC-Mass spectra show that the main product is an acetylene chloride. Additionally, the phase transition temperature of polyacetylene chloride at 325 ˚C was examined by differential scanning calorimeter (DSC).
An amperometric TCE sensor by using a Pb electrode in an organic electrolyte was developed. The optimal pretreating and sensing conditions were found to be 1.0 M pretreatment HNO3 concentration, 30 min pretreatment time, -2.10 V (vs. Ag/Ag+ with 0.1 M tetrabutylammonium perchlorate (TBAP) in AN) sensing potential, 250 rpm agitation rate in a 0.025 M tetrabutylammonium tetrafluoroborate (TBAT) organic electrolyte. The response time and the sensitivity were 10 s and 7.15 μA/cm2-ppm, respectively. Additionally, at least 4 months stability for the prepared working electrode was also obtained. The correlation of the sensing response current, id, and TCE concentration, CL, is id=7.15CL in the range from 50 to 250 ppm TCE. The rate constant of (TCE) at mass-transfer control was found to be 4.86810-3 (cm-s)-1.
The TCE sensor by using an electrodeposited a Pb modified graphite electrode in an organic electrolyte was studied. The best electrodeposition conditions of the prepared working electrode were 20 mA/cm2 electrodeposition current density, 25 ˚C electrodeposition temperature and 2 hrs. Additionally, the optimal sensing conditions were -2.10 V sensing potential (vs. Ag/Ag+ with 0.1 M tetrabutylammonium perchlorate (TBAP) in acetonitrile (AN) solution), 100 rpm agitation rate, and at 25 ˚C with 0.01 M tetrabutylammonium tetrafluoroborate (TBAT) electrolyte concentration in AN solution were obtained in this system. Under the optimal sensing conditions, the results indicated that the sensitivity and response time were 7.06 μA/cm2-ppm and 15 s (90% response time), respectively. Furthermore, the stability is at least 60 days for prepared electrode. Additionally, the correlation of sensing response current, id, and trichloroethylene (TCE) concentration, CL, is id=7.06CL in the range from 100 to 700 ppm TCE. The rate constant of (TCE) at mass-transfer control was found to be 4.8110-3 (cm-s)-1.
Electrochemical detection of trichloroethylene with an electrodeposited Pb modified was designed. The optimal conditions for the preparation of the electrodeposited Pb modified electrode were obtained which 0.1 M pretreatment HNO3 concentration, 60 min pretreatment time, 20 mA/cm2 electrodeposition current density, 30 ˚C electrodeposition temperature and 2 hrs. The optimal sensing conditions such as -2.10 V sensing potential (vs. Ag/Ag+ with 0.1 M tetrabutylammonium perchlorate (TBAP) in acetonitrile (AN) solution), 155 rpm agitation rate, and at room temperature with 0.01 M tetrabutylammonium tetrafluoroborate (TBAT) electrolyte concentration in AN solution were obtained in this system. Under the optimal sensing conditions, the results indicated that the sensitivity and the response time were 1.06 μA/cm2-ppm and 20 s (90% response time), respectively. Furthermore, the stability is at least 60 days for prepared electrode. Additionally, the correlation of sensing response current, id, and trichloroethylene (TCE) concentration, CL, is id=1.06CL in the range from 50 to 700 ppm TCE. The rate constant of (TCE) at mass-transfer control was found to be 7.21710-4 (cm-s)-1.
A novel electrochemical TCE sensor using an electrodeposited Pb modified Pt-Ti thin film electrode was successfully developed and well characterized. The prepared conditions of the electrodeposited Pt-Ti thin film working electrode were obtained as 310-3 torr sputtering pressure, 20 min sputtering deposition time ,30 watts sputtering power, 18.75 mA/cm2 and 2 hrs under room temperature. Optimal sensing conditions were found to be -2.10 V (vs. Ag/Ag+ with 0.1 M tetrabutylammonium perchlorate (TBAP) in acetonitrile (AN) solution) sensing potential, 250 rpm agitation rate. At room temperature, the sensitivity and response time was 2.86μA/cm2-ppm and 15 s (90% response time), respectively. Furthermore, the prepared electrode had over 15 cycles of reusability, and the stability is least 180 days. Additionally, the correlation of sensing response current, id, and trichloroethylene (TCE) concentration, CL, is id=2.86CL in the range from 100 to 700 ppm TCE. The rate constant of (TCE) at mass-transfer control was found to be 2.43410-3 (cm-s)-1.
In this study, the framework of the TCE sensor with an electrodeposited Pb modified Pt-Ti thin film electrode can be obtained excellent sensing performances such as the sensitivity, the response time, the reusability and the stability. Additionally, the electrodeposited Pb modified Pt-Ti thin film electrode can be combined with microfabrication technique for the design of TCE sensor. Therefore, the electrochemical TCE sensor using an electrodeposited Pb modified Pt-Ti thin film electrode in TBAT organic electrolyte showed promising features for commercial application.
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