2014-12-012024-05-15https://scholars.lib.ntu.edu.tw/handle/123456789/666063摘要：砷的毒害是一種全球性的地下水污染問題，而台灣現有之地下水質砷污染來源包含土壤污染列管場址，因土壤中砷傳輸至地下水體，導致地下水中砷濃度超過地下水污染管制標準，以及西南沿海與宜蘭地區地下水，若農業及漁業用水引用當地地下水做為水源，造成對生物或人體的潛在危害性。目前處理技術是利用薄膜法、吸附劑吸附法、化學沉澱與電混凝法等程序去除水中過量之砷，以避免人體遭受砷之危害。然而傳統砷處理技術存在成本高、薄膜表面積垢、無法有效處理低濃度含砷水樣、並需添加化學藥劑、耗能且產生大量污泥等問題，故開發創新性的技術，提升砷的處理效能是相當重要的。 電容去離子技術(Capacitive Deionization, CDI)為一種節能、清淨、無需使用化學藥劑，且不產生二次污染物之新穎電化學處理技術，其原理是利用外加電場的控制與奈米孔洞碳電極的高比表面積，基於電荷分離機制，先以外部供電方式充電，在處理水體中產生電場，利用庫倫作用力將水中離子電吸附於電極表面上，在奈米孔洞間形成電雙層，進而產出乾淨水體。值得注意的是，與傳統的砷處理技術相比，CDI更適合處理含低濃度污染物之水體，恰符合砷在天然水體中低濃度之特性，其可利用高比表面積之碳電極提供電吸附/電沉積反應位置，過程中能源需求低、無須添加化學藥劑，不會產生二次污染物，且電極可重覆使用。故與傳統的砷處理技術相比，利用CDI去除水中砷相當具有競爭優勢與應用潛力。 本研究計畫之目的在於評估CDI技術於移除地下水中無機砷之可行性，顯著提升對於五價砷與三價砷的去除效能，達到其與水體分離的目的。研究內容包含研析五價砷與三價砷之去除機制與移除效率，瞭解電場對於砷型態間的轉變之影響，與地下水體中不同物質的存在對於砷的選擇性之影響，以及發展實驗室規模CDI模組系統，應用於處理地下水體的砷污染，評估CDI技術應用於模擬/實場水體中移除砷之發展潛力。本研究的成果具有學術貢獻與應用價值，可突破傳統地下水質砷污染處理技術之瓶頸，並降低對於民眾健康的潛在危害風險。<br> Abstract: Arsenic poisoning via groundwater is one of worldwide problems. Arsenic can be introduced in water through nature sources and anthropogenic sources, resulting in higher concentrations of arsenic in groundwater. Importantly, it is found that in some areas of Taiwan, the arsenic concentrations are much higher than the groundwater quality standards. However, traditional water treatments, such as adsorption, reverse osmosis, and electrocoagulation, have many limits for the removal of arsenic from aqueous solutions at low concentrations. Therefore, the development of effective, energy-saving, and environmentally friendly separation techniques to remove arsenic from groundwater is a promising issue. Capacitive deionization (CDI), or referred to electrosorption process, has been regarded as a novel water purification technology, which has many advantages including low operating pressure, low energy consumption, no chemical demand, no secondary waste, easy regeneration. The mechanism behind CDI to remove ionic species from aqueous solutions is based on the charge separation, in which nanoporous carbon electrodes are charged and discharged to store and to release large quantities of ions, respectively. It is worth noting that as comparing with other traditional water treatment processes, CDI is especially suitable for the removal of arsenic at low concentrations in groundwater. It is proposed that under the assistance of electric filed, arsenic can be electrostatically separated from water to form the electrical double layer inside charged nanopores of carbon electrodes, or to be reduced by electrodeposition on the electrode surface. The main purpose of this study is to evaluate the feasibility of conducting CDI technology for the removal of arsenic from groundwater. This research project have the following specific contributions: (1) the fundamental understanding of arsenic removal by using the CDI process, (2) the fate and transformation of arsenic in groundwater affected by the CDI process, (3) the effects of natural substances in groundwater on the selective removal of arsenic, (4) the development of a laboratory-scale CDI module with high water production rate to deal with the contaminated groundwater via field sampling. The obtained results can improve the current knowledge of treatment techniques in arsenic removal, providing useful information for the practical filed applications of arsenic contamination.電容去離子技術砷地下水整治Capacitive DeionizationArsenicGroundwater remediation