污染土壤中五氯酚為微-奈米尺寸片錳礦之氧化礦化及脫氯作用

Oxidative Mineralization and Dechlorination of Pentachlorophenol in Contaminated Soils by Micro-nano Size δ-MnO2

林文玲(Wen-Ling Lin)

指導教授 ： 張簡水紋 ； 王敏昭

朝陽科技大學/理工學院/環境工程與管理系/碩士(2010年)

摘要

含氯的芳香族有機化合物在環境中是非常毒之有機化合物，而且是屬於對人類致癌物之一。五氯酚Pentachlorophenol (PCP)是疏水性離子性有機化合物，通常在多種工業中被當作製造原料來使用。儘管五氯酚已被政府明令禁止使用多年，但台灣南部仍有大面積的五氯酚污染場址。化學氧化方法已被提出是可作為復育五氯酚現地污染場址方法之一，利用微奈米尺寸片錳礦(δ-MnO2)，其為錳氧化物之一，也是天然存在於土壤環境中的礦物質之一。?了模擬五氯酚污染場址中，土壤底層處於厭氧和無光照系統下，利用一種自行設計之氣體釋放與吸收反應瓶，在無光照條件下，研究有氧或無氧(通氮氣除氧)狀態下，添加δ-MnO2對五氯酚進行氧化礦化脫羧作用和脫氯作用釋放出Cl–。
研究結果顯示，在有氧、無光照與無微生物活動條件下，添加δ-MnO2可促進五氯酚進行氧化礦化脫羧作用和脫氯作用釋放出Cl–。然而，在無氧(通氮氣除氧)狀態下，添加δ-MnO2對五氯酚進行的氧化礦化脫羧作用則明顯減少，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可對五氯酚進行非生物性破壞芳香苯環而釋放CO2 和Cl–。進而，計算釋放出的CO2和Cl–的莫耳比例，來推測不同反應系統下的反應機制。由於模擬近似污染場址的條件，在實驗室所獲得之參數和數據，對於規劃五氯酚現地污染整治過程是非常有用的，特別是可作為土壤底層包含地下水飽和層中，對五氯酚去毒作用的指導方針。

關鍵字

脫氯作用 ； 礦化 ； 片錳礦 ； 五氯酚

並列摘要

Chlorine–containing aromatic organic compounds are very toxic organic compounds in the environments and regarded as one of human carcinogens. Pentachlorophenol (PCP) is hydrophobic ionizable organic compound (HIOC) and is commonly used as manufacturing material in many industries. There is a large area of PCP contaminated site in southern part of Taiwan though PCP has been prohibited to use by the government authority for many years. Model chemical oxidation method has thus been proposed to remediate the PCP contaminated site in situ using micro-nano size δ-MnO2, which is one of manganese oxides and naturally occurring mineral in soil and associated environments. In order to simulate the anaerobic and dark situation of deep soil layers in PCP contaminated site, one kind of self-designed gas absorption and release reaction flask has been used to investigate the oxidative decarboxylation as well as mineralization and dechlorination to release Cl– of PCP enhanced by δ-MnO2 under air or N2 atmosphere and dark condition.
The results showed that δ-MnO2 enhanced the oxidative decarboxylation as well as mineralization and dechlorination to release Cl– of PCP under air and dark in the absence of microbial activity. However, under N2 atmosphere oxidative decarboxylation as well as mineralization of PCP was drastically reduced but dechlorination to release Cl– of PCP became the dominant reaction. This clearly indicates abiotic ring cleavage of aromatic ring of PCP to release CO2 and Cl– enhanced by δ-MnO2. Further, calculated mole ratios of released CO2 to Cl– were thus used to sketch the reaction mechanisms of different reaction systems. Due to similar simulated condition in laboratory to that in contaminated site, the parameters and respective data obtained thus have highly potential to be used as a guideline for planning the remediation process of PCP contaminated site in situ and especially for the detoxification of PCP in deeper soil profile including groundwater saturated layer.

並列關鍵字

pentachlorophenol ； δ-MnO2 ； mineralization ； dechlorination

參考文獻

行政院環境保護署，土壤酸鹼值測定法，NIEA S410.62C。

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