含界面活性劑水溶液中有機污染物揮發特性之探討

Volatilization of Organic solutes from surfactant solutions

陳秀芬(Hsiu-Fen Chen)

指導教授 ： 李俊福

國立中央大學/工學院/環境工程研究所/碩士(2006年)

摘要

本研究群先前曾提出一個揮發模式-表面損失揮發模式，用以說明環境條件對有機物揮發速率之影響，故本研究之主要內容是延續先前之表面損失揮發模式之觀念，並利用有機化合物質傳係數KOL值之變化，解釋有機物污染物自界面活性劑水溶液中或氣相擾動條件下之揮發機制。本研究中所選擇之化合物包括相對高水溶解度(Sw)及高亨利常數(H)之單環芳香族化合物及相對低水溶解度(Sw)及低亨利常數(H)之有機氯農藥；界面活性劑為十二烷基苯磺酸鈉，其濃度則包含低於及高於臨界微胞濃度之範圍；選擇風速大小條件為0、0.2、0.5、1.0、2.0及4.0 m/s。
研究結果指出(1) 水中添加界面活性劑可有效抑制低水溶解度化合物之揮發量，對於高水溶解度之有機物抑制作用並不明顯，但是當界面活性劑濃度超過臨界微胞濃度時，低水溶解度化合物揮發量將明顯減少。(2)高亨利常數化合物在不同風速條件下之質傳係數KOL高於低亨利常數化合物，但以有風及無風條件下之KOL/KOLO比值而言，卻得到相反的結果。(3)利用化學結構相近之參考化合物，作為估算有機物自界面活性劑溶液中之揮發行為，確實是可行的。(4)溶液中同時加入界面活性劑及風速條件，可以發現有機物受風速之影響量是大於界面活性劑之抑制作用。(6)利用新建立的α值(有機物在液體交界與溶液中濃度比值)，可用來解釋當低水溶解度化合物存在於界面活性劑溶液時，此溶質也許會被濃縮於界面上。

關鍵字

界面活性劑 ； 表面損失揮發模式 ； 揮發 ； α值 ； 質傳係數KOL

並列摘要

In the previous researches, a volatilization model, surface depletion rate-limiting (SDRL), has been presented to elucidate the effects of environmental conditions on volatilization rates of organic solutes. Here, the SDRL model has been extended to explain the mechanisms of organic solutes in the surfactant solution or under gas turbulence, based on the changes in overall mass transfer coefficient (KOL) of the organic solutes. The selected compounds consist of monaromatic compounds with the relatively higher water solubilities (Sw) and Henry’s law constant (H), as well as pesticides with relatively lower Sw and H. The surfactant used in this research is DBS with concentration from below critical micelle concentration (CMC) to above CMC. The wind speeds selected include 0, 0.2, 0.5, 1.0, 2.0, 4.0 m/s.
The obtained results indicated that (1) the added surfactant could effectively inhibit the volatilization of the low Sw pesticides, but less-effective on the high Sw solutes. Especially, when the surfactant concentrations exceed CMC, the low Sw solutes exhibit the more volatilization reduction; (2) KOL values of high H solutes is higher than those of low H solutes under the various wind speeds, but the KOL/KOLO (wind /static) ratios show an opposite result; (3) it is feasible to estimate the KOL values of the organic solutes using those with similar chemical structure as a reference compound; (4) the effect of wind speeds on the selected solute volatilization was significant as the solutes existing in the surfactant solutions under the gas turbulence; (5) an new α value (ratio of solute concentration in bulk phase to interface phase) resulting from SDRL was established to explain the solutes possibly was concentrated at the interface when the low Sw solutes exist in the surfactant solutions.

並列關鍵字

surfactant ； α values ； surface depletion rate-limiting ； volatilization ； mass transfer coefficient KOL

參考文獻

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