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

• Main Authors: Wen-Ling Lin, 林文玲
• Other Authors: Shui-Wen ChangChien
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/48067075600659444048

碩士 === 朝陽科技大學 === 環境工程與管理系碩士班 === 98 === 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.