Degradation of organic contaminants in groundwater using alkaline-activated persulfate

[[abstract]]甲基第三丁基醚(methyl tert-butyl ether, MTBE) 及1,2- 二氯乙烷 (1,2-dichloroethane, 1,2-DCA)為地下水常見之污染物，前者廣泛利用於汽油添加劑， 後者為氯乙烯(vinyl chloride, VC)之製備原料，兩者皆具有不易整治及疑似人體致癌 性之特性。本研究以鹼活化過硫酸鹽程序處理受MTBE 及1,2-DCA 污染之地下水， 針對不同pH 及不同污染物之實驗因子進行探討，以瞭解鹼活化過硫酸鹽程序所需 之pH 值以及其對不同污染物處理之效果。此外，以工業廢棄物活化過硫酸鹽之可 行性，亦於本研究中進行探討。本研究之主要目的包括：(1)探討鹼活化過硫酸鹽程 序所需之pH 值；(2)探討鹼活化過硫酸鹽程序對不同污染物之處理成效；及(3)評估 工業廢棄物鹼活化過硫酸鹽之可行性。 實驗結果顯示，鹼活化過硫酸鹽程序能有效加速1,2-DCA 之降解。鹼活化過硫 酸鹽程序會降低MTBE 降解速率，但能有效抑制反應過程中副產物TBA (tert-butyl alcohol)、TBF (tert-butyl formate)的生成。工業廢棄物-轉爐石(basic oxygen furnace slag, BOF slag)能驅動過硫酸鹽鹼活化，有效加速1,2-DCA 之降解，且沒有重金屬溶 出的現象。本研究之成果將可提供相關受污染場址進行整治之參考，但鹼活化過硫 酸鹽氧化法去除污染物之機制複雜，因此未來應用於不同污染物處理前，仍有必要 針對各種污染物逐一謹慎評估其適用性，以避免降解延遲之情形發生。[[abstract]] Methyl tert-butyl ether (MTBE) and 1,2-dichloroethane (1,2-DCA) are common groundwater pollutants. MTBE is widely used as a gasoline additive while 1,2-DCA is used for the production of vinyl chloride (VC). Both pollutants are difficult to be remediated and may cause cancer. In this study, alkaline-activated persulfate was used to treat MTBE- and 1,2-DCA-contaminated groundwater. Batch experiments were conducted under different pH to determine the required pH for alkaline-activated persulfate reaction. Furthermore, the potential of alkaline-activated persulfate by industrial waste was also evaluated. The main objectives were to: (1) investigate the required pH for alkaline-activated persulfate; (2) evaluate the degradation efficiency of MTBE and 1,2-DCA by alkaline-activated persulfate; and (3) evaluate the potential of industrial waste to drive alkaline-activated persulfate process. Results show that alkaline-activated persulfate can effectively accelerate the degradation of 1,2-DCA. Alkaline-activated persulfate reduced the degradation rate of MTBE and inhibited the production of MTBE-degrading byproducts, tert-butyl alcohol (TBA) and tert-butyl formate (TBF). Persulfate activated by industrial waste basic oxygen furnace slag (BOF Slag) enhanced the degradation of 1,2-DCA. No heavy metals were released from BOF slag during the experiments. Results of this study would be helpful to design a practical system for the treatment of contaminated sites. Since the mechanisms of contaminant removal by alkaline-activated persulfate are complicated, feasibility study is necessary III before alkaline-activated persulfate is applied to other target compounds to avoid the retardation of contaminant degradation.[[note]]碩