以電化學處理螯合劑復育受重金屬污染土壤之模擬洗出液

Electrochemical Treatment of Simulated Washing Effluent in Remediation of Heavy Metal Contaminated Soil Using Chelating Agent

王秀雯(Shiow-Wen Wang)

指導教授 ： 莊瑞鑫

元智大學/工程學院/化學工程與材料科學學系/碩士(1998年)

摘要

本實驗是利用電膜沉積處理螯合劑沖洗復育受重金屬污染土壤之模擬洗出液。陰極液分三部分討論，第一部份為單成分Pb-EDTA溶液；第二部分為雙成分的Cu-EDTA-Pb溶液；第三部份則為Cu-Pb-Cd-Cr-Zn- EDTA溶液。實驗的陽極板採用鈦鍍氧化銥電極，陰極板則採用不銹鋼板。實驗以不同電流密度（46.3~185 A/m2），不同的陰極液初始pH值（1.47~6.0），不同螯合金屬濃度（5~20 mM），不同螯合金屬Cu/Pb比例（0.25~4）進行。
由實驗結果得知，單成分Pb-EDTA及雙成分Cu-EDTA-Pb的陰極液中螯合金屬的初始濃度越高（>15 mM），金屬的回收率及電流效率也越高。陰極液的螯合金屬在pH較低時，螯合金屬的金屬離子濃度較多，則金屬Pb的回收率（>95%）及電流效率（>60%）會較高。雙成分Cu-EDTA-Pb中，Cu導電性較佳，高Cu/Pb比例下，金屬Cu、Pb回收率（>90%）及電流效率（>30%）會較高。多成分Cu-Pb-Cd-Cr-Zn-EDTA中，Cu還原電位最低，Zn最高，則螯合金屬的金屬回收速率以Cu最快，其次為Pb、Cd，最後為Zn。

關鍵字

復育土壤 ； 電化學處理 ； 陽離子薄膜

並列摘要

The objective of this research is remediation of heavy metal contaminated soil with chelating agent by electrochemical transfering of simulated washing effluent. The three cases were dealt with (1) single component, Pb(Ⅱ); (2)binary component, Cu(Ⅱ) and Pb(Ⅱ)；(3)multi component, Cu(Ⅱ)、Pb(Ⅱ)、Cd(Ⅱ)、Cr(Ⅵ) and Zn(Ⅱ). An iridium oxide coated on titanium (IrO2 / Ti) was used as the anode, and a staniless steel was used as the cathode. Experiments were carried out at different current densities(46.3~185 A/m2), different initinal catholyte pH(1.47~6.0), different catholyte chelated metal concentrations(5~20 mM), and different catholyte chelated metal ratio of Cu/Pb (0.25-4).
An economically feasible efficiency and recovery 95% of metals and EDTA could be acheieved if the concentration of the chelated metal was high in all cases. The higher current efficiency was obtained in strong acidic catholyte solutions, and in higher current density. The higher current efficiency and higher recovery of metals was acheieved if the metal ratio (Cu/Pb) was higher in binary component case. The raction rate of recovery Cu(Ⅱ)was the fastest, then was Pb(Ⅱ), Cd(Ⅱ), and Zn(Ⅱ) was the slowest rate could be gotten in multi component case.

並列關鍵字

remediation soil ； electrochemical treatment ； cation membrane

參考文獻

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