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|標題:||pH dependence of persulfate activation by EDTA/Fe(III) for degradation of trichloroethylene||作者:||Liang, C.J.
|關鍵字:||Sulfate radical;Groundwater;Remediation;In situ chemical oxidation;in-situ remediation;hydrogen-peroxide;aqueous-solution;ferrous ion;oxidation;tce;peroxydisulfate;complexes;radicals;acid||Project:||Journal of Contaminant Hydrology||期刊/報告no：:||Journal of Contaminant Hydrology, Volume 106, Issue 3-4, Page(s) 173-182.||摘要:||
The ability of free ferrous ion activated persulfate (S(2)O(8)(2-)) to generate sulfate radicals (SO(4)(-)) for the oxidation of trichloroethylene (TCE) is limited by the scavenging of SO(4)(-) with excess Fe(2+) and a quick conversion of Fe(2+) to Fe(3+). This study investigated the applicability of ethylene-diamine-tetra-acetic acid (EDTA) chelated Fe(3+) in activating persulfate for the destruction of TCE in aqueous phase under pH 3, 7 and 10. Fe(3+) and EDTA alone did not appreciably degrade persulfate. The presence of WE in the EDTA/Fe(3+) activated persulfate system can induce faster persulfate and EDTA degradation due to iron recycling to activate persulfate under a higher pH condition. Increasing the pH leads to increases in pseudo-first-order-rate constants for TCE, S(2)O(8)(2-) and EDTA degradations, and Cl generation. Accordingly, the experiments at pH 10 with different EDTA/Fe(3+) molar ratios indicated that a 1/1 ratio resulted in a remarkably higher degradation rate at the early stage of reaction as compared to results by other ratios. Higher persulfate dosage under the EDTA/Fe(3+) molar ratio of 1/1 resulted in greater TCE degradation rates. However, increases in persulfate concentration may also lead to an increase in the rate of persulfate consumption. (C) 2009 Elsevier B.V. All rights reserved.
|Appears in Collections:||環境工程學系所|
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