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年度	111	專案性質	實驗性質
專案類別	研究專案	研究主題	整治
申請機構	淡江大學	申請系所	水資源及環境工程系
專案主持人	李奇旺	職等/職稱	教授
專案中文名稱	以硫化奈米零價鐵及高硫酸複合鹽整治技術處理受三氯乙烯汙染之地下水
中文關鍵字	硫化奈米零價鐵,高級氧化程序,硫酸根自由基,重質非水相液體
專案英文名稱	Treatment of trichloroethylene polluted groundwater by the integration of sulfidized nanoscale zero-valent iron and persulfate-based remediation technology
英文關鍵字	sulfidized nanoscale zero-valent iron, advanced oxidation processes, sulfate radicals, DNAPL
執行金額	900,000元
執行期間	2022/5/1 至 2023/4/30
計畫中文摘要	三氯乙烯為地下水常見之含氯有機污染物之一。因其比水重之非水溶相液體且自然降解程度不佳的特性，一旦洩漏至地表下溶於地下水中，即會造成地下水污染及整治的困難。目前常規且已普遍應用於 TCE 污染的土壤和地下水復育方法 中的處理效果及環境友善可持續性方面，還是有其限制。例如，抽取處理法僅對溶解相污染物有效。且處理中需添加表面活性劑來改善含水層的質傳效率以縮短操作時間，但也同時增加現場廢水處理的難度和引發進一步污染物遷移和擴散問題。鐵基納米材料(例如 nZVI) 因其高反應性和比表面積相當大的特性，常被用於處理重金屬、氯化有機化合物和無機化合物等各種污染物的環境修復。 nZVI 會因為快速聚集而形成大顆粒，造成表面積大幅減少而降低反應效率。 nZVI 也因與水中的溶氧、硝酸鹽或水反應，於 nZVI 表面生成鐵氧化層 表面鈍化 ))，阻礙電子傳送，使 nZVI 失去活性，導致反應性快速降低，增加處理成本。因此，使用 nZVI 於受污染的土壤或地下水修復需克服nZVI 團聚、表面鈍化，反應壽命短、對汙染物的反應無針對性等問題。研究學者提出各種 nZVI 改質方法來改善 上述的缺點。目前改質方法中，最受矚目為使用硫化合物對nZVI 進行化學改性。得到的硫化 nZVI( 非常有效地改善 nZVI 團聚、表面鈍化、反應壽命短、及對汙染物反應針對性差的問題。 SnZVI 表面具有較好的疏水性，可降低與水反應的速率，延長藥劑的生命週期；此外，對疏水性污染物 例如 TCE) 更具有選擇性處理的優點。相較於傳統化學法合成的 SnZVI ，製程所使用的化學藥劑易形成污染環境的廢水。本研究以電化學硫化程序製備 SnZVI ，於缺氧的水溶液中，將水溶液中的 Fe 2+ 或是 Fe 3+ 於陰極還原成零價 鐵。生成的零價鐵可直接與反應槽中的硫化物生成 Fe/FeS 奈米顆粒。製程中減少化學藥劑的使用，更加友善環境，更符合環保署的綠色整治原則。本研究以壓克力製成之 2D 沙箱實驗，透過三層不同粒徑之沙土 粗沙、細沙及粉沙 來模擬 TCE 在土壤中的污染分布狀況；並於沙箱側面設置 10 個採樣孔，以了解 TCE 於不同粒徑的土壤層濃度降解的狀況。本研究符合目前土水整治技術傾向，以整合方式結合多種不同的整治技術進行現地整治，結合硫化奈米零價鐵與高級氧化程序，可提供現地整治技術多一項選擇。
計畫英文摘要	As one of the common chlorinated organic pollutants in groundwater, Trichloroethylene (TCE) is very difficult to remediate once it leaks into the subsurface and dissolves in groundwater due to the characteristics of the dense non aqueous phase liquid ( DNAPL). The common groundwater remediation technologies currently employed still face limitations in their treatment effectiveness and environmental friendliness and. For example, pump and treat (P&T) is effective only for dissolved contaminants. In additi on, surfactants is needed to improve the mass transfer efficiency of the contaminants to reduce the remediation time. However, the addition of surfactants might impose difficulty for the on site wastewater treatment and cause further pollutant migration an d diffusion problems. Iron based nanomaterials, such as nZVI , are often used in environmental remediation of soils or groundwater polluted with heavy metals, chlorinated organic compounds, and inorganic compounds due to their high reactivity and considerable specific surface area. However, the reactivity and effect iveness of nZVI are compromised by the rapid aggregation of nZVI, resulting in a large reduction in surface area. The reactions of nZVI with dissolved oxygen, nitrate in water to form an iron oxide passive layer also hinder electron transfer and make nZVI inactive, resulting in a rapid decrease in reactivity and an increase in processing costs. Therefore, the use of nZVI in the remediation of contaminated soil or groundwater needs to overcome the problems of nZVI agglomeration, surface passivation, short re action life, and unselective response toward to pollutants. Various nZVI modification methods have been proposed to improve the above shortcomings. Among these modification methods, the chemical modification of nZVI using sulfur compounds has received th e most attention. The resulting sulfided nZVI (SnZVI) is very effective in improving the problems of nZVI agglomeration, surface passivation, short reaction lifetime, and unselective response toward to pollutants. Due to its hydrophobicity, the reaction of SnZVI with water is minimized, prolonging the reaction time of SnZVI; in addition, the reaction selectivity toward hydrophobic pollutants (such as TCE) is enhanced. Compared with the traditional chemical methods for SnZVI synthesis, the proposed electroc hemical sulfidation procedure for SnZVI preparation in this study is more environmentally friendly and more in line with the green remediation principles of the Environmental Protection Agency. In this study, a 2D sandbox made of acrylic will be used to si mulate the distribution of TCE pollution in the soil through three layers of sand with different particle sizes (coarse sand, fine sand and silt sand). A sampling hole will be used to explore the degradation of TCE in soil layers with different particle si zes. This study is in line with the current trend of soil and water remediation technology which emphasize the combination of different remediation technologies for on site. Combining sulfidized nanoscale zero valent iron and advanced oxidation processes p rovide one more option for on site remediation technology.