EPA-94-U1U1-04-008

094

3,363 千元

2005/03/04

2005/12/31

林財富

永續發展室(停用)

國立成功大學創新育成中心

土壤及地下水

現地氧化,過硫酸鹽,過錳酸鹽,三氯乙烯

ISCO,persulfate,permanganate,TCE

林竫京

許益源

林財富

06-2006321

tflin@mail.ncku.edu.tw

現地氧化技術 (In-Situ Chemical Oxidation, ISCO) 由於使用快速、方便、加上可以氧化DNAPL污染物，導致該技術具有對於含氯碳氫化合物具有極大之處理潛力。研究探討過硫酸鹽 (persulfate) 和過錳酸鹽 (permanganate) 兩種氧化劑，在不同P/T莫耳濃度配比下，添加/不添加緩衝溶液下之TCE處理效能及氧化劑消耗量。另一方面，溶液系統中之pH值和OPR也被監測。研究顯示，添加緩衝溶液之系統，可以有效維持系統之pH值，避免土壤及地下水酸化，造成進一步傷害。高莫耳濃度氧化劑與TCE(P/T)比之氧化劑具有較高之TCE去除率。溶液系統中有機物之存在(此處為甲醇)，會明顯影響TCE之氧化動力，其他陰離子，如氯離子、溴離子或硝酸根等存在時，會對氧化劑效能產生不同程度之抑制現象。溴離子之抑制現象最嚴重，依序為氯離子，硝酸根之壓抑程度則不明顯。而越高濃度陰離子所產生之抑制現象也越嚴重。批次實驗結果顯示，相同的高錳酸鉀濃度下，高濃度的TCE，生成的二氧化錳顆粒越大，低濃度配比形成的顆粒則呈細微膠羽，模型槽實驗結果則顯示，高錳酸鹽在砂箱中經過3天後，固體物經XRD分析結果顯示，有二氧化錳、高錳酸鉀等成分，但沉澱物造成之阻塞效果並不明顯，應該與TCE在系統中濃度不高有關。此外，實驗與模式結果顯示，模型槽中氯化鈉追蹤劑與氧化劑移動途徑類似，顯示可以以追蹤劑作為氧化劑移動之參考。

現地氧化,過硫酸鹽,過錳酸鹽,三氯乙烯

0000121522.pdf

9MB

[期末報告]公開完整版

2006/3/1 上午 12:00:00

Two oxidants, persulfate and permanganate, were employed to explore the performance of in-situ chemical oxidation (ISCO) of chlorinated solvent in an artificial aquifer. To evaluate the effectiveness of the oxidants of destroying TCE contaminant in an artificial aquifer, the batch-scale experiment was first conducted in this project. The kinetics of heat-assisted persulfate and permanganate oxidation of trichloroethylene (TCE) in aqueous solutions at various oxidant concentrations, ionic strength and anionic species was studied. It is found that the systems with buffered solution have a nearly constant pH value during the experimental period. A higher oxidant/TCE molar ratio in the oxidation experiments resulted higher efficiencies of TCE destruction by persulfate and permanganate. The presence of organic compounds (methanol in this case) may significantly slow the oxidation kinetics of TCE by persulfate. The TCE oxidation kinetics was also influence by the presence of three anions, nitrate, chloride, and bromide, at different extent. For nitrate, the influence is the smallest and may be attributed to the effect of increasing ionic strength. For both chloride and bromide, in addition to the ionic strength effect, it is speculated that the two anions were radical scavengers that caused additional reduction of reaction rates. In addition, the effect is more substantial for permanganate that persulfate. The formation of small particles during permanganate oxidation was monitored in both batch and sand-box experiments. At the same permanganate concentration, larger particles formed at higher TCE concentration in the batch experiments. This is also observed in the sand-box experiments, in which only very small amount of precipitates were observed, perhaps due to low TCE concentration in the system. After analyzed by XRD, the precipitates were mainly potassium permanganate and MnO2. In addition, the flow pattern of tracer and oxidants were similar, suggesting that the tracer may be used to simulate the flow of the oxidants in the sand box system.

ISCO,persulfate,permanganate,TCE