96年度「綠色奈米技術之開發及應用：環境友善性奈米級零價鐵模擬現地整治土壤/地下水污染技術開發及應用」
| 中文摘要 | 本研究旨在研究開發具環境友善性之奈米級零價鐵，並將其應用於整治模擬之土壤/地下水污染，為達成此計畫目標，本研究係以三氯乙烯(TCE)作為標的污染物，探討於水溶液及土壤污染整治試驗中，採用添加可溶性澱粉作為分散劑之奈米鐵懸浮液，將其注入模擬的受TCE污染的飽和土壤水平管柱，並分別嘗試藉助電動力法及蠕動幫浦驅動奈米鐵懸浮液，使之與TCE反應，並觀察其整治成效。首先，利用化學還原法製備奈米級零價鐵，經X-光繞射分析證實為鐵元素，由掃描式電子顯微鏡觀測得知奈米鐵粒徑分佈介於40~60 nm間，而TEM觀測得知顆粒粒徑約為10-20 nm。此外，本研究合成之奈米鐵經BET比表面積分析儀測得其比表面積為37.2 m2/g。 奈米級零價鐵之穩定性探討係使用可溶性澱粉與聚丙烯酸(PAA)作比較，結果顯示使用3 wt% 之可溶性澱粉其奈米鐵懸浮液穩定性較佳。 對於添加可溶性澱粉之奈米級零價鐵懸浮液以去除水溶液中三氯乙烯試驗，首先，奈米級零價鐵懸浮液對TCE經可溶性澱粉分散改質後確實可提高TCE之降解成效。TCE降解試驗結果顯示，當降解時間為150分鐘，初始濃度為10 mg/L時，其降解效率約為60 %；當初始濃度為2 mg/L時，其降解效率則約為80 %左右；而當初始濃度為0.1 mg/L時，其降解效率約為75 %。 在模擬土壤/地下水現地污染整治方面，本研究係利用添加可溶性澱粉之奈米鐵懸浮液結合電動力技術處理水平土壤(砂質黏壤土及砂土)管柱系統中的三氯乙烯，並與奈米鐵懸浮液結合蠕動幫浦驅動技術進行比較。奈米鐵懸浮液結合電動力技術的試驗係以電位梯度為1 V/cm，每日注入20 mL之奈米鐵懸浮液 (鐵濃度為1.25 g/L)於選定之電極槽內，實驗結果顯示，奈米鐵懸浮液之注入位置以陽極槽較佳，實驗結果顯示成效最佳之組別可去除土壤中近99 %之TCE濃度。 比較奈米級零價鐵懸浮液結合電動力土壤管柱試驗及以蠕動幫浦驅動之土壤管柱試驗，結果顯示電滲透流之流率遠大於所採用之蠕動幫浦操作條件，利用電動力驅動奈米零價鐵懸浮液對TCE降解效果較佳；反之，利用蠕動幫浦驅動奈米級零價鐵並無法順利將其傳輸至出流水槽，因此，在靠近出流水槽處之TCE殘餘量較多，也導致其菌落之生長受到抑制。 由於本研究係採用生物可分解之水溶性澱粉當作奈米級零價鐵之分散劑，且所製備之奈米鐵懸浮液注入模擬之受污染下環境中，可藉助電動力法之驅動傳輸而將標的污染物有效降解，且反應土體之總菌落數增加。因此，本研究所開發之現地污染整治技術可謂是具環境友善性，值得推廣應用。 | ||
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| 中文關鍵字 | 奈米級零價鐵懸浮液, 電動力法, 現地整治 | ||
基本資訊
| 專案計畫編號 | EPA-96-U1U1-02-102 | 經費年度 | 096 | 計畫經費 | 1950 千元 |
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| 專案開始日期 | 2007/06/01 | 專案結束日期 | 2008/03/31 | 專案主持人 | 楊金鐘 |
| 主辦單位 | 永續發展室(停用) | 承辦人 | 執行單位 | 國立中山大學環境工程研究所 |
成果下載
| 類型 | 檔名 | 檔案大小 | 說明 |
|---|---|---|---|
| 期末報告 | 96年度綠色奈米技術之開發與應用-奈米鐵整治技術.pdf | 2MB | [期末報告]公開完整版 |
Development and Application of Green Nanotechnology: Technology Development and Application of Environmentally Benign Nanoscale Zero-Valent Iron for In Situ Remediation of Simulated Soil/Groundwater Pollution
| 英文摘要 | The objectives of this research were to prepare an environmentally benign nanoscale zero-valent iron (also known as nanoiron) and then to apply it to remediate a simulated soil/groundwater contamination. Trichloroethylene (TCE) was selected as the target pollutant in this study. First, nanoiron was prepared by the borohydride reduction method. During the growth of iron nuclei in the solution, a soluble starch (3 wt%) among other dispersants was determined to be the best to form the stabilized nanoiron slurry (“nanoiron slurry” for short) for later uses. X-ray diffraction (XRD) analysis has identified iron as the single crystalline substance. The image of transmission electron microscopy (TEM) indicated that the particle size of nanoiron ranged from 10 to 20 nm. This size range is in accord with that of calculated by Scherrer formula. Due to the aggregation of nanoiron, a size distribution of secondary particles was determined to be 40-60 nm as shown in the micrograph of scanning electron microscopy (SEM). A fluffy substance over the surface of nanoiron (as shown in TEM image) was confirmed to be starch by SEM mapping of elements on the surface of nanoiron. In the batch tests the nanoiron slurry (nanorion dose: 1.25 g/L; soluble starch: 3 wt%) was found to be capable of removing TCE in aqueous solution. For the initial TCE concentrations of 10 mg/L and 0.1 mg/L, after a reaction time of 150 min, the respective TCE degradation efficiencies were determined to be about 60 % and 75 %. After the above preliminary tests, such nanoiron slurry was further verified for its capability of degrading TCE in soil and groundwater. In this series of tests, laboratory-prepared, saturated TCE-bearing soil was firmly packed in horizontal soil columns to simulate the groundwater flow in the subsurface. Soil specimens of sandy clay loam and sand were selected to compare the transport behaviors of nanoiron slurry in the simulated subsurface environment as driven by electrokinetics (EK) and pumping using a peristaltic pump, respectively. In the EK tests, 20 mL of nanoiron slurry was injected to the selected electrode (anode or cathode) reservoir daily with a constant applied electric potential gradient of 1 V/cm and for a reaction time of 7 days. The initial TCE concentration in sandy clay loam was in the neighborhood of 285 mg/kg, whereas about 68 mg/kg in sand. Experimental results have shown that the anode reservoir is a better injection spot as compared with its counterpart. Under the circumstances, a TCE degradation efficiency of about 99 % could be obtained. In the pumping tests, however, it is only applicable to sand with a flow rate of 0.29 mL/min. Further, even for an operation time of 25 h it was unable to transport nanoiron slurry from the influent reservoir to the effluent reservoir. The soil fraction near the effluent reservoir was found to have a high residual TCE concentration. As compared with the pumping tests, the EK tests were found to be much capable of transporting nanoiron slurry in the simulated groundwater system resulting in a much greater TCE removal. Moreover, the number of microorganism colony in soil was found to be increased as a result of the injection nanoiron slurry. This might be ascribed to the fact that starch molecules surrounding iron nanoparticles have provide a good carbon source for the growth of microorganism colony in the neighborhood. Based on the research findings obtained above, it might be claimed that the nanoiron slurry prepared in this study is an environment-friendly one. By combining the injection of such nanoiron slurry with EK, a green environmental nanotechnology has been developed for the remediation of TCE in the subsurface. | ||
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| 英文關鍵字 | Nanoscale Zero-Valent Iron Slurry, Electrokinetic Method, In Situ Remediation | ||