- 期刊
以陰離子界面活性劑清洗受低濃度BTEX污染之土壤
Treatment of Low-Level BTEX-Contaminated Soils by Anionic Surfactant Washing
摘要
本研究係以土壤管柱做為土壤沖排的試驗裝置，並以陰離子界面活性劑系統清洗含低濃度苯（benzene）、甲苯（toluene）、乙苯（ethylbenzene）、二甲苯（xylenes）（簡稱BTEX）污染土壤，並對復育效果作仔細的評估與比較。本實驗所採用的陰離子界面活性劑為十二烷基磺酸鈉鹽（sodiumdodecylsulfate, SDS）。此外，本研究對於去離子水清洗BTEX污染土壤的效果及其與界面活性劑系統之差異、BTEX在界面活性劑沖洗後於管柱中的殘留濃度分布情形以及界面活性劑對土壤性質之影響亦有詳細之探討。結果顯示，界面活性劑系統的清洗效果優於去離子水。此外，陰離子界面活性劑濃度越高越能有效移除土壤中BTEX，原因由於臨界微胞濃度（critical micelleconcentration, CMC）越低越有助於提高界面活性劑的有效微胞濃度。由土樣示蹤劑試驗（tracertest）的研究結果發現，以陰離子界面活性劑清洗低BTEX濃度污染土壤，可達到63至95%的去除率，且陰離子界面活性劑之劑量並不會改變土壤本身的性質。本研究之成果可作為以界面活性劑淋洗法整治石油碳氫化合物污染土壤之設計參考。
並列摘要
Soil contamination generated by petroleum hydrocarbons, including benzene, toluene, ethylbenzene and xylene isomers (BTEX), has raised concern around the world. Soil flushing is the process of treating polluted soils with water, surfactants, or solvents, and it is usually feasible for the remediation of petroleum-hydrocarbon contaminated soils. Surfactant-enhanced flushing was developed from the conventional pump-and-treat method. A mixture of water and surfactants is often applied to polluted soils and groundwater to improve the solubility of the pollutants during soil flushing. The objective of this study was to investigate the effects of applying anionic surfactants flushing on the treatment of low and high level BTEX-contaminated soils. A surfactant, sodium dodecylsulfate (SDS, anionic type), was used as a washing agent in the column experiments. Column studies were conducted to evaluate the efficiency of BTEX removal from unsaturated porous media using different concentrations of SDS for soil flushing. The soil column [4.2 cm (ID) × 12 cm (L)] was packed with low-level BTEX-contaminated soils (100 and 1,000 mg/kg) and DI water was pumped into the column with a flow rate of 11 ± 1 mL/min. Results from the column study show that BTEX removal efficiencies varied from 63 to 95% when 0.5 ~ 2% (v/v) of SDS was pumped through the system. Higher BTEX removal efficiency was obtained when the higher surfactant concentration was applied. The results from this study provide insights into the surfactant washing technology, and will be useful in designing a scaled-up system for field applications.