界面活性劑Tomadol® 91-6搭配大豆油淋洗三氯乙烯之效率評估

Evaluation of trichloroethylene flushing efficiency by surfactant Tomadol® 91-6 combined with soybean oil

余彥辰(Yu Yan-Chen)

指導教授 ： 葉桂君

國立屏東科技大學/工學院/環境工程與科學系所/碩士(2021年)

https://doi.org/10.6346/NPUST202100279

摘要

整治土壤地下水污染發展了許多相關技術，其中界面活性劑淋洗技術(Surfactant Enhanced Aquifer Remediation, SEAR)是公認有效的方法之一，現階段界面活性劑淋洗法已發展的相當完善，但SEAR運用也面臨部分困難，如傳統灌注皆以連續式灌注界面活性劑水容易進行淋洗整治，在整治過程中不僅會消耗大量的界面活性劑造成環境負擔，還可能造成二次污染亦會提高整治成本，所以有不少案例會使用其他物質當助界劑來代替部分界面活性劑提升淋洗效率，以降低界面活性劑的使用量使整治成本及二次污染的風險降低。
本研究污染物為三氯乙烯，實驗以界面活性劑T91-6搭配大豆油，進行相行為實驗模擬T91-6與TCE在接觸及完全混合之結果，評估作用機制、大豆油增溶性和成效，篩選適合的T91-6以及大豆油濃度進行土壤管柱淋洗。以各濃度T91-6分析數據探討淋洗效益和相關成本，以制定最佳的現地整治方案。

結果顯示，在無添加大豆油時進行相行為實驗，界面活性劑T91-6與高TCE DNAPL污染接觸或完全混合，上層液皆為透明澄清而乳化相高度會隨著T91-6濃度提高而變高，隨著污染物比例降低，上層液顏色依然澄清但乳化相高度則不會隨著T91-6濃度提高而變高，當添加大豆油與界面活性劑T91-6完全混合進行相行為實驗時，發現微乳液(T91-6+Oil)與高、中、低TCE DNAPL污染物接觸或完全混合，在0.1%和0.5% T91-6實驗瓶中上層液皆為粉色，且隨著添加越多大豆油(1.0%和2.0%)，上層液粉色變化越明顯，而1.0%和2.0%T91-6上層液依然呈現透明澄清，在高TCE DNAPL條件下，乳化相高度比未添加大豆油時還高且隨著T91-6濃度提高而變高，隨著TCE DNAPL污染物比例降低，乳化相高度沒有隨著T91-6濃度上升能變高，但包覆且溶解TCE的效果越好。
接續進行土壤管柱淋洗試驗，在相同TCE污染濃度下，土壤管柱淋洗試驗中以濃度0.5% T91-6搭配1.2%大豆油有著最佳的去除效益，在0.5% T91-6添加1.2%大豆油時比未添加大豆油多去除了管柱內16%的三氯乙烯，證實添加大豆油對T91-6有著良好的增溶能力，在1.0%、2.0% T91-6添加大豆油對TCE也有著對良好的去除效果，但經成本分析及比較整治效益後顯得成本昂貴，且期望值不高，雖然數據顯示T91-6與大豆油配置成的微乳液對TCE有良好的整治效果，但管柱內還是會剩餘少許TCE在土壤中，因此可以使用整治列車(Treatment train)的整治概念，以更經濟的整治方法對最後殘留的污染物進行整治，就能以最合適的整治策略進行現地整治處理。

關鍵字

三氯乙烯 ； 界面活性劑淋洗法 ； 助界劑 ； 大豆油

並列摘要

Many technologies have been developed for the remediation of soil and groundwater pollution.Among them, the surfactant enhanced aquifer remediation (SEAR) is considered as one of the effective methods. At present, even though the SEAR has been developed quite well, it still faces some difficulties. For example, the standard practice of SEAR continuously injects surfactant solution into aquifers. However, this will not only consume a large amount of surfactant and increase the remediation cost during the SEAR process, but also creates an environmental burden and secondary pollution. Therefore, some substances are used as auxiliary agents to improve the flushing efficiency.
The target pollutant in this study is trichloroethylene (TCE). The tested surfactant is T91-6 and soybean oil is used to enhance T91-6 efficiency. The contact and complete mix between T91-6 and TCE are used to evaluate the phase behavior of TCE, T91-6 and soybean oil. The soil column flushing test uses the best parameters from the phase behavior study. The removal efficiency and cost of TCE DNAPL by various combination of T91-6 and soybean oil are evaluated.
The phase behavior experiment results show that without soybean oil, when the surfactant T91-6 is in contact or completely mixed with high amount of TCE DNAPL, the upper aqueous layer is transparent and clear, and the height of emulsified phase increase with higher T91-6 concentrations. As the proportion of TCE DNAPL decreases, the color of the upper layer is still clear, but the height of the emulsified phase will not increase as T91-6 concentration increases. When the T91-6 micelles contain soybean oil, the microemulsion phase is more significant in both contact and completely mixed systems. The color of upper aquous layers for 0.1% and 0.5% T91-6 turns pink, and with more addition of soybean oil (1.0% and 2.0%), the pink color is more obviously. At high amount of TCE DNAPL, more emulsified phase is formed than the no soybean sets. As the proportion of TCE DNAPL decreases, the upper layer liquids are still pink, transparent and clear, but the height of the emulsified phase does not increase with the T91-6 concentrations.
In the soil column flushing test, the mixture of 0.5% T91-6 with 1.2% soybean oil has the best removal efficiency and cost benefit. It removes 16% more TCE than T91-6 only. This indicates that the addition of soybean oil enhances T91-6 ability to remove TCE. The addition of soybean oil at a concentration of 1.0% and 2.0% of T91-6 also has a good removal effect on TCE, but the cost analysis appears to be expensive. Although the result of this study shows that the microemulsion of T91-6 and soybean oil has a good remediation effect on TCE, there is still TCE remaining in the soil column. It is suggested that the concept of the treatment train can be used to remediate the remaining TCE followed after the SEAR using soybean enhanced T91-6 flushing reagent.

並列關鍵字

Trichloroethylene ； surfactant leaching method ； auxiliary agent ； soybean oil

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