研究不同萃取方法對土壤中銅的去除機制及電動力法的處理效率

The study on copper removal efficiency and mechanisms of various extraction reagents and electrokinetics in contaminated soils

施彥鴻(Yan-Hong Shi)

指導教授 ： 章日行

朝陽科技大學/理工學院/環境工程與管理系/碩士(2009年)

摘要

本研究以振盪萃取的方式，了解土壤中銅的去除效率，並結合電動力系統來探討對銅污染土壤的處理成效。以實場銅污染土壤為對象進行土壤樣品採集、前處理及分析土壤的基本物化特性，同時利用不同萃取劑對土壤中不同型態的鍵結銅進行脫附以尋找最佳萃取程序。試驗中土水比為1：10，振盪時間為2小時，萃取液包括0.01M EDTA、pH2 鹽酸＋檸檬酸、pH2 硝酸＋檸檬酸、0.25M NaOH及0.085M 二亞硫酸鈉＋檸檬酸鈉等。試驗數據經整理分析後，得知EDTA可萃取土壤中可交換態及碳酸鹽態的銅，對於有機物態及鐵錳氧化態的銅較難以萃取。當以EDTA與NaOH交互萃取，可使土壤中銅之去除率提高約20％。針對鐵錳氧化態，使用二亞硫酸鈉＋檸檬酸鈉可使土壤中銅之去除率再提高約10％。因此獲得最佳萃取流程及去除效率。當以以最佳的萃取流程結合電動力法來進行土壤整治時，即採用0.01 M EDTA、0.25 M NaOH及0.085 M二亞硫酸鈉＋檸檬酸鈉之操作液，其參數設定為：陽極為石墨板、陰極為不鏽鋼板、電壓梯度為1 V/cm、極板間距為15 cm及操作時間為30天等操作因子。

關鍵字

土壤整治 ； 電動力法 ； 銅污染土壤 ； EDTA

並列摘要

This research focused on understanding the soil removal efficiency of copper by the oscillatory extraction approach; then, combined with the electrokinetics systems to explore the treatment performance of copper contaminated soil. The copper-contaminated soil from the real-site was collected for soil samples. The use of different extracts for removing different copper species from the soil in order to find an optimal extraction procedure. The extraction tests were conducted by the soil-water ratio of 1:10, oscillation time of 2 hours. Extracts included 0.01M EDTA, hydrochloric + citric acid, nitrate + citric acid, 0.25M NaOH and 0.085M Sodium hydrosulfite + sodium citrate. Results indicated that the EDTA could remove the copper species of soil exchangeable and carbonate. When the EDTA and NaOH extraction was used alternatively, the removal efficiency of copper in the soil increased about 84 %. For the copper of Fe-Mn oxides, the use of sodium hydrosulfite + sodium citrate could further increase the removal efficiency of copper by more 10 %. When the extraction process applied to the electrokinetics, that is, use of 0.01 M EDTA, 0.25 M NaOH and 0.085 M Sodium hydrosulfite + sodium citrate solution for EK operation, which could remove around 55 % copper from the soil during 30-day treatment.

並列關鍵字

copper-contaminated soils ； EDTA ； electrokinetics ； soil remediation

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