運用催化劑δ-MnO2 在有氧及無氧條件下處理水中三氯乙 烯之脫氯與脫羧之研究

Dechlorination and Decarboxylation of Trichloroethylene (TCE) caralyzed by δ-MnO2 in TCE Contaminated Water Under Aerobic/Anerobic Conditions

張喬揚(Chaio-Yang Chang)

指導教授 ： 王敏昭 ； 張簡水紋

朝陽科技大學/理工學院/環境工程與管理系/碩士(2011年)

摘要

含氯有機物如三氯乙烯(Trichloroethylene)等含氯脂肪族碳氫化合物
(Chlorinated Aliphatic Hydrocarbons, CAHs)，為地下水中常見之受關切化學
物質，而含氯脂肪族碳氫化合物因具有低沸點、化學安定性及強溶解等特
性被廣泛使用在各種商業用途。由於儲存槽的破裂、地面油品的意外洩漏
及人為蓄意排放，造成土壤與地下水中污染的主要原因。現地化學氧化法
為目前對於含氯有機污染整治極具潛力的整治方法之ㄧ，可處理地表下污
染區域而不受地面結構物之干擾，而且氧化劑之高氧化性能夠使污染物迅
速破壞縮短復育時程。因此，本研究使用自行合成之微奈米尺寸片錳礦
(δ-MnO2)，其為錳氧化物之ㄧ，也是天然存在於土壤環境中的礦物。模擬
於土壤底層受三氯乙烯污染之地下水，利用先前學者自行設計之氣體吸收
反應瓶，探討在有氧或無氧(通氮氣)狀態下，添加δ-MnO2對三氯乙烯進行
礦化作用和脫氯作用釋放出Cl－，之後再以曝氣反應瓶注入空氣及氮氣比較
兩模組氧化與還原反應之差異性。
研究結果顯示，在有氧與無微生物的活動下，添加δ-MnO2可促進三氯
乙烯進行氧化礦化脫羧作用和脫氯作用釋放出Cl－。然而，在無氧(通氮氣)
的狀態下，添加δ-MnO2對三氯乙烯進行礦化脫羧作用則較有氧狀態下減
少，而脫氯作用釋放出Cl－則成為主要反應。這明確指出添加δ-MnO2可對
三氯乙烯進行非生物性破壞其結構而釋放出CO2及Cl－，且隨著時間增加所
II
測得之CO2及Cl－皆有明顯上升的趨勢，而在未添加污染物的狀態下則無此
趨勢。進而，計算釋放出CO2及Cl－的莫耳比例，來推測不同反應系統下之
反應機制。由實驗室模擬受污染場址處理所獲得之參數與數據，可用於未
來規劃現地受三氯乙烯污染場址之整治過程是非常有用的，特別是可作為
土壤底層之地下水飽和層中對三氯乙烯降解去除作用的指導方針。
關鍵字： 三氯乙烯、δ-MnO2、地下水、化學氧化

關鍵字

δ-MnO2 ； 地下水 ； 化學氧化 ； 三氯乙烯

並列摘要

Trichloroethylene and other chlorinated organic compounds such as
chlorinated aliphatic hydrocarbons are widely used in a variety of commercial
purposes and are common pollutants in groundwater due to low boiling point,
high solubility and chemical stability. Considerable amount of soil and ground
water have been contaminated as a result of leaks from underground storage
tanks, man-made accidental emissions and improper disposal. Chemical
oxidation of organic chlorine is one of the potential remediation methods
where the process is within the source zone in subsurface environment, and the
oxidant having high oxidation properties could reduce the complex
contaminants to smaller non-pollutant compounds by rapid destruction.
Manganese oxide is a very common mineral component present in the mineral
soil. Hence, in this study, synthesized micro nano-sized particles of δ-MnO2
were used as catalyst, simulations at the bottom of the soil pollution of
groundwater by TCE, usage of formerly designed gas absorption reaction flask,
investigating under aerobic and anaerobic (passing nitrogen) conditions,
adding δ-MnO2 for mineralization, decarboxylation (CO2 evolution) and
dechlorination (release of Cl－) reactions of TCE. After completion of the
experimental process of TCE under aerobic and anerobic conditions in
presence δ-MnO2, the two modules of oxidation and reduction reactions
differences were compared.
The results showed that under aerobic conditions having no microbial
activity, addition of δ-MnO2 promotes oxidation of TCE mineralization,
decarboxylation and dechlorination. However, in the absence of oxygen
(passing nitrogen), addition of δ-MnO2 promoted mineralization of TCE, but
IV
the amount of decarboxylation is less compared to aerobic conditions, while
dechlorination was found to be the major reaction. These experiments
implicates that δ-MnO2 under non-biological activity conditions causes
breakdown of TCE structure and releases CO2 and Cl－, and when the reaction
time period is increased, increase in the release of CO2 and Cl－ is observed,
whereas this trend is not observed in absence of pollutants. The release of CO2
and Cl－molar ratio was calculated under different reaction mechanisms. By the
laboratory simulation of contaminated sites and the data obtained from
different parameters, this process can be extended for further studies on
TCE contaminated soil and water sites and this remediation process is very
useful, especially for the underlying groundwater saturated soil layer of
contaminated TCE.

並列關鍵字

δ-MnO2 ； chemical oxidation ； groundwater ； Trichloroethylene

參考文獻

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