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年度	100	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	國立中山大學	申請系所	新興污染物研究中心
專案主持人	楊金鐘	職等/職稱	教授
專案中文名稱	利用電動力法現地整治汞污染土壤先期研究
中文關鍵字	碘化鉀輔助電動力法；現地整治；汞污染土壤
專案英文名稱
英文關鍵字	Potassium Iodide-Assisted Electrokinetic Process；In Situ Remediation；Mercury-Contaminated Soil
執行金額
執行期間	2011/11/26 至 2012/11/25
計畫中文摘要	本先期研究旨在評估利用電動力程序現地整治真實汞污染土壤之可行性。台灣早期之鹼氯工廠所產生之汞污泥及其不當處理/處置所衍生之土壤/地下水污染問題，至今仍未能完全得到妥善解決。本研究利用實驗室規模之電動力整治系統氣密式砂箱反應器探討碘化鉀輔助電動力整治工法之操作參數、評估其對於汞之整治效率、及估算此工法之整治費用，進而評估此整治工法之可行性及應用潛能。砂箱反應器中所佈設之模擬未飽和層及飽和層土壤係採集自國內某實際汞污染場址土壤 (汞濃度為3,000-5,000 mg/kg)，並使用0.1 M KI水溶液及/或真實地下水當作陰、陽極槽液及土壤間隙水，分別以施加定電壓 (1 V/cm) 或定電流 (20 mA) 進行1-14日不同期程之8組電動力整治試驗。碘化鉀輔助電動力試驗結果顯示：(1) 汞與碘化鉀形成水溶性離子態之HgI42-移向陽極端為主要處理機制，而以形成水溶液相之Hg2I2且藉由電滲透流移向陰極端為次要處理機制；(2) 經由總汞質量平衡分析，推測碘化鉀輔助電動力整治工法尚有穩定化的處理機制足以使得汞形成殘餘態金屬化合物，而無法由王水消化法予以前處理及分析；(3) 本整治工法對於汞污染土壤在整治過程並不會有汞氣體逸散之虞；及 (4) 本整治工法8組試驗之平均總汞去除率為27.96-62.77%，具有技術可行性，且其整治費用 (27-77元/每公克汞) 與其他工法相當，具經濟可行性。因此，本先期研究採用之碘化鉀輔助電動力整治工法實具有現地整治真實汞污染土壤及底泥之應用潛能，未來如何將此整治工法實場應用仍有待進一步研究與評估。
計畫英文摘要	The objective of this preliminary study was to evaluate the feasibility of using the electrokinetic (EK) process for in situ remediation of actual Hg-contaminated soil. Subsurface mercury contamination due to improper treatment and disposal of Hg-containing sludge generated from chlor-alkali factories has been a headache in Taiwan for decades. To resolve this problem, a novel EK process was proposed in this research. In this work an EK remediation system, including a gas-tight sand-box reactor with monitoring wells & caps, DC power supply, and electrodes of various materials, was first installed. Then an actual Hg-contaminated soil (Hg concentration of 3,000 to 5,000 mg/kg) was collected, characterized, and filled in the soil compartment of sand-box reactor simulating the unsaturated zone and saturated zone. In addition, 0.1 M KI lixiviant and/or actual groundwater were used as anolyte, catholyte and soil pore water. At this stage, an electric field was applied to the EK remediation system using a constant voltage mode (i.e., 1 V/cm) or constant current mode (i.e., 20 mA) for eight tests with different remediation time ranging from 1 to 14 days. The following are the research findings obtained using the potassium iodide-assisted electrokinetic (KI-assisted EK) process in this work: (1) migration of HgI42- (originated from chemical reaction of Hg and KI in aqueous solution) toward the anode is the primay mechanism for Hg removal, whereas the transport of dissolved Hg2I2 toward the cathode end by electroosmositic flow is consided the secondary removal mechchnism for Hg; (2) through the mass balance of total Hg in the sand-box reactor, it is postulated that there might exist a mechanism relevant to Hg stabilization rendering the formation of unknown residual metallic Hg compound that is non-dissolvable by aqua regia digestion and for subsequent chemical analysis; (3) the emission of Hg vapor would not take place in the KI-assisted EK process; (4) the KI-assisted EK process is considered to be technically and economically feasible as compared with other Hg remediation technologies. It is believed that further studies are needed before the KI-assisted EK process could be implemented in the real world.