常見受TCE污染之地下水整治方法中，現地化學氧化法-Fenton法具有良好的處理效率，由參考文獻中得知Fenton法最主要關鍵為pH適用範圍需在pH2~4，否則易產生大量氫氧化鐵污泥，因此在整治期間常需加入大量藥劑控制pH值；且H2O2之半衰期短，故亦常需要重複添加氧化劑，導致整治成本增加。 本研究欲利用零價鐵催化兩種不同的氧化劑 ─ 過氧化氫與過硫酸鹽，分別進行TCE降解批次式瓶杯實驗與以滲透性反應牆形式進行零價鐵管柱堵塞實驗，比較不調整pH值情形下，ZVI/H2O2與ZVI/PS兩系統降解TCE之效率與零價鐵牆堵塞情形。 實驗結果顯示TCE經由ZVI/H2O2與ZVI/PS兩系統反應，經10天後兩系統降解效率相當，降解效率皆能達九成以上。以人工地下水添加相同濃度H2O2與PS氧化劑流入零價鐵層實驗中，在未調整pH值情形下，發現添加H2O2之零價鐵層較添加PS之更易造成堵塞，顯示在不調整pH值情形下，ZVI/PS較ZVI/H2O2系統更具持久且能有效去除TCE。 更進一步實驗，發現零價鐵層堵塞情形會隨PS添加濃度與pH值影響，濃度越高、pH值越低則可減少氫氧化鐵沉澱物產生，降低堵塞程度。 Fenton method is one of the common, in situ chemical oxidation technologies for TCE contaminated ground water. Past studies have shown that the control of pH at 2-4 to prevent Fe(OH)3(S) sludge generated was the key condition for Fenton method. Therefore, this method needs a large of amount chemical reagent to control pH during remediation period. Also, the oxidants must be repeatedly added due to the short half-life of H2O2, resulting in increasing remediation cost. Two kinds of oxidants which use zero value iron (ZVI) as the catalyst, hydrogen peroxide and persulfate, were compared in the study. The batch jar test of TCE degradation and ZVI column obstructive property experiment were conducted to investigate the system of ZVI/H2O2 and ZVI/PS on TCE degradation efficiency and obstructive situation of ZVI column. The results showed that the TCE degradation efficiency of ZVI/H2O2 and ZVI/PS were similar with over 90% efficiency achieved after ten days of reaction. Without the pH control, ZVI column was more prone to be clogged in ZVI/H2O2 system than in ZVI/PS system, revealing that the latter is more persistent than the former. Furthermore, the ZVI column obstructive property is affected by persulfate concentration and pH; increasing the persulfate concentration or lowering the pH will reduce the Fe(OH)3(S) sludge generated. Overall, ZVI activated persulfate oxidation offers a persistent and effective way for remediation of TCE contamination.
