以光纖光催化技術處理地下水中含氯有機物之現地模場研究

在行政院環境保護署推動地下水環境調查及監測以後，發現國內地下水受有機溶劑污染場址眾多，以含氯有機污染物之污染事件所占比例最大，其中以四氯乙烯(Perchloroethene,PCE)和三氯乙烯(Trichloroethene,TCE)為最普遍使用之含氯有機溶劑。由於含氯有機污染物為潛在致癌性毒物質，對人體健康影響大，且屬於重質非水相溶液(dense non-aqueous phase liquid, DNAPL)進入環境後，污染會持續向土壤及地下水層進行擴散，進而造成嚴重污染的情況。本研究以在屏東縣一個受含氯有機物污染之地下水場址，利用地下水採樣分析、流速流向和水位測量等方式了解現地場址之條件，依據調查結果規劃並設計於現地可行之新穎光催化反應處理系統。研究中，以一套適合應用於地下水層較厚之水中光源機，將光源有效延伸至地下水污染層，降低光損失。在現地試驗方面，針對試驗井進行薄膜介面探測作業系統 ( Membrane Interface Probe, MIP )分析，優先找到污染層及熱點。試驗以被動式採樣袋進行井中污染物濃度空白分析，得到背景資料確認後，再以光纖光催化系統應用現地試驗，進行不同觸媒種類(商業用Degussa P-25 TiO2和N-doped TiO2)在紫外光(395 nm)和可見光(400~800 nm)照射下，對於現地受污染之地下水含氯有機物之探討，試驗最後進行對溶解性有機碳(DOC)之影響和系統處理氯離子(Cl-)濃度之變化以了解其光降解成效。在紫外光和可見光，以在可見光照射光觸媒處理效果較佳，在可見光和N-TiO2條件下，1,1,2-三氯乙烷、四氯乙烯及三氯乙烯皆可達到100 %去除率，而1,1,-二氯乙烯可達到98 %去除效率，而在溶解性有機碳去除效率方面，試驗模場之受污染地下水之溶解性有機碳(DOC)濃度，確實會隨著系統進行而達到去除；試驗後氯離子濃度均有增加的現象，代表光纖光催化系統應用於處理現地地下水之污染確實有光降解作用發生。

關鍵字

光催化；覆膜光纖；三氯乙烯；四氯乙烯；現地整治

並列摘要

After the environmental protection department of the Executive Yuan has promoted the investigation and monitoring of groundwater environment, it has been found that there are many sites contaminated by organic solvents in Taiwan, among which chlorine containing organic pollutants account for the largest proportion. Among them, tetrachloroethylene (PCE) and trichloroethylene (TCE) are the most commonly used chlorinated organic solvents. As chlorinated organic pollutants are potential carcinogenic substances, they have a great impact on human health, and belong to heavy non-aqueous phase liquid, After DNAPL enters the environment, the pollution will continue to spread to the soil and groundwater layer, which will cause serious pollution. In this study, a novel photocatalysis treatment system was designed for a chlorinated organic compound contaminated groundwater site in Pingdong County by using groundwater sampling analysis, flow velocity and water level measurement. In this study, a set of water light source machine suitable for thick underground water layer can effectively extend the light source to the polluted layer of groundwater and reduce the light loss, in the experiment, the passive sampling bag was used for blank analysis of the pollutant concentration in the well. After the background information was confirmed, the field test was carried out by using the optical fiber photocatalytic system. Different catalyst types (commercial Degussa P-25 TiO2 and N-doped TiO2) were tested in ultraviolet (395 nm) and visible light (400-800 nm) In order to understand the effect of photodegradation, the effects on dissolved organic carbon (DOC) and the concentration of chloride ion (Cl-) in the polluted groundwater were studied. Under the conditions of visible light and visible light, the removal rate of 1,1,2-trichloroethane, tetrachloroethylene and trichloroethylene can reach 100% under visible light and n-TiO2, while 1,1,2-trichloroethane, tetrachloroethylene and trichloroethylene can reach 100%,The removal efficiency of dichloroethylene can reach 98%. In terms of the removal efficiency of dissolved organic carbon (DOC), the concentration of dissolved organic carbon (DOC) in the polluted groundwater of the test field will indeed be removed with the system going on; after the test, the concentration of chloride ion has increased, which indicates that the optical fiber photocatalytic system has the effect of photodegradation when applied to the treatment of in-situ groundwater pollution.

並列關鍵字

photocatalysis ； coated optical fiber ； trichloroethylene ； tetrachloroethylene ； on site remediation

參考文獻

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