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年度	113	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	東海大學	申請系所	環境科學與工程學系
專案主持人	陳柏安	職等/職稱	助理教授
專案中文名稱	延展式流體電容去離子系統處理含砷地下水之研究
中文關鍵字	地下水, 砷, 電容去離子, 電化學
專案英文名稱	Extendable Fluidized Capacitive Deionization System for the Treatment of Arsenic-Contaminated Groundwater
英文關鍵字	Groundwater, Arsenic, Capacitive Deionization, Electrochemistry
執行金額
執行期間	2024/12/1 至 2025/11/30
計畫中文摘要	本研究針對我國地下水中常見之無機砷污染問題，發展新穎性水處理技術「延展式流體電容去離子系統」(Extendable fluidized capacitive deionization, E-FdCDI)，以期克服傳統電容去離子技術(CDI)於處理高流量或低濃度污染物時所面臨的效能限制。傳統CDI系統常受限於電極固定間距(約2 mm)、低處理通量與電極結垢問題，而本研究所提出之E-FdCDI系統整合流動式碳電極與可延展模組設計，可有效提升處理流速與系統穩定性，為地下水中砷離子去除提供高效且具擴展潛力之技術方案。電極材料採用天然生質廢棄物製備具高比表面積與多孔隙結構之活性碳，並進一步作為流體電極材料應用於E-FdCDI系統中。比表面積測試結果顯示，自製活性碳(特別是柚子皮來源)之比表面積高達2100 m²/g，顯著優於一般商業活性碳(約1200 m²/g)，有利於提升電吸附容量與反應表面活性。此外，進一步引入Fe/Fe3C@C改質電極以提升電化學活性，結果顯示其於長時間操作下可維持71%以上的除砷效率。然而，考量其製備成本與模廠應用，後續實驗採用未改質碳電極作為主要材料。掃描式電子顯微鏡、X光繞射儀及傅立葉轉換紅外線光譜儀等表徵結果亦驗證材料具良好結構穩定性與官能基分佈，適用於長時間電化學操作環境。實驗室電吸附系統測試模擬砷溶液，E-FdCDI 可穩定操作於高達 15 mL/min 之流速條件，為一般實驗室級反應器流量(約5 mL/min)之三倍處理能力，於不同初始濃度條件(0.1、1、5、及10 ppm)下皆展現穩定除砷效能。於5 mg/L三價砷溶液中可達96.1%之最高去除率，在0.1 mg/L低濃度條件下仍能維持74.3%去除效率，顯示該系統於不同砷污染程度水體中皆具良好適應性。此外，藉由循環伏安分析進一步驗證三價砷於電場作用下氧化轉換為五價砷之機制，並觀察到明顯氧化峰與電流密度增加趨勢，顯示 E-FdCDI 系統除具物理吸附能力外，亦可同時能降低砷毒性並提升整體去除效能。在環境干擾測試方面，腐植酸存在時會因錯合反應導致除砷速率下降；而於多離子(Ca2+、Mg2+、Na+、K+)共存條件下，系統仍維持穩定除砷表現。即使在多離子與腐植酸同時存在的複雜條件下，去除效率仍可保持在80%以上，顯示其具良好抗干擾特性。重複循環操作測試亦證實電極於50次操作後除砷效率僅下降約5%，展現優異再生性與長期穩定性。E-FdCDI系統除具傳統CDI所強調之環境友善、低能耗、及無需化學添加劑之特性外，更可模組化與高流速操作，使其具應用於中高污染濃度地下水治理之潛力，未來可望推展至現地含砷污染場址作為永續水資源處理技術之一。
計畫英文摘要	This study addresses the issue of inorganic arsenic contamination commonly found in groundwater in Taiwan by developing an innovative water treatment technology, the Extendable Fluidized Capacitive Deionization system (E-FdCDI). The E-FdCDI system was designed to overcome the performance limitations of conventional capacitive deionization (CDI) techniques, which typically face challenges such as fixed electrode spacing (approximately 2 mm), low treatment throughput, and electrode fouling when treating high flow rates or low pollutant concentrations. By integrating fluidized carbon electrodes with an extendable modular configuration, the proposed E-FdCDI system effectively enhances mass transfer, stability, and operational flexibility, providing a high-efficiency and scalable solution for arsenic removal from groundwater. The electrode materials were prepared from natural biomass wastes, specifically acacia wood and pomelo peel, to produce activated carbon with a high specific surface area and porous structure. The resulting activated carbon exhibited a specific surface area of up to 2100 m2/g, significantly higher than that of commercial activated carbon (approximately 1200 m2/g), thereby improving electro-adsorption capacity and surface reactivity. In addition, Fe/Fe3C@C-modified electrodes were introduced to enhance electrochemical activity, showing over 71% arsenic removal efficiency during long-term operation. However, considering the cost and reproducibility for pilot-scale applications, subsequent experiments were conducted using unmodified carbon electrodes as the primary material. Characterization analyses, including scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR), confirmed the structural stability and suitable surface functionality of the prepared materials for long-term electrochemical operation. Laboratory-scale electro-adsorption experiments using simulated arsenic solutions demonstrated that the E-FdCDI system operated stably at a high flow rate of 15 mL/min, which is approximately three times that of conventional bench-scale CDI reactors (around 5 mL/min). The system achieved consistent arsenic removal performance under various initial concentrations (0.1, 1, 5, and 10 ppm). A maximum removal efficiency of 96.1% was achieved for a 5 mg/L As(III) solution, while a removal efficiency of 74.3% was maintained at a low concentration of 0.1 mg/L, indicating strong adaptability across different contamination levels. Cyclic voltammetry (CV) analysis further verified the electrochemical oxidation of As(III) to As(V) under the applied electric field, revealing distinct oxidation peaks and increased current density. This result indicates that the E-FdCDI system not only removes arsenic through physical electro-adsorption but also simultaneously reduces arsenic toxicity and enhances overall removal efficiency through an oxidation–adsorption dual mechanism. In environmental interference tests, the presence of humic acid slightly decreased the arsenic removal rate due to complexation effects. Under multi-ion coexistence conditions (Ca2+, Mg2+, Na+, K⁺), the system maintained stable performance, and even under the combined influence of humic acid and multiple ions, the removal efficiency remained above 80%, demonstrating strong anti-interference capability. Repeated cycling tests confirmed excellent regeneration and long-term stability, with only about 5% efficiency loss after 50 operational cycles. Overall, the E-FdCDI system exhibits several advantages, including environmental friendliness, low energy consumption, chemical-free operation, modular scalability, and high flow-rate capability. These features make it a promising technology for the treatment of medium to highly arsenic-contaminated groundwater. The E-FdCDI system has the potential to be further developed for on-site remediation applications and contribute to sustainable water resource management in Taiwan.