以微乳液整治受Anthracene污染之土壤

Remediation of Anthracene contaminated soil by microemulsion

許貴欽(Guei-Chin Shiu)

指導教授 ： 泣奉華

崑山科技大學/工程學院/環境工程研究所/碩士(2009年)

摘要

由於工業的快速發展，使得石化燃料、有機溶劑被大量使用，然而因為人類的使用不當對環境造成危害，也對人類健康有極大的威脅。因為土壤污染在環境中不易被人發覺，往往需等到有異味產生才會被發現。土壤之污染物大多數都屬於疏水性有機化合物 (hydrophobic organic compounds, HOCs)，許多研究証實界面活性劑能有效的應用於HOCs污染土壤整治，然而要如何提高界面活性劑對HOCs的去除效果，且考量到洗滌後之界面活性劑溶液處理不易，如界面活性劑的濃度影響微生物進入微胞中分解污染物。因此，能夠將整治後的界面活性劑溶液重複再使用，將能降低整治成本。
本研究以10倍臨界微胞濃度 (critical micelle concentration, CMC)之陰離子界面活性劑 (sodium dodecyl sulphate, SDS) 溶液90 mL (SDS之1倍CMC為2.23 g/L) 與大豆油10 mL乳化後之微乳液，整治受多環芳香烴化合物 (polycyclic aromatic hydrocarbons, PAHs) 污染之土壤，探討是否能提高受PAHs污染之整治效果。為了確認SDS與大豆油乳化之效果，透過觀察溶液靜置後是否會產生分層現象，再以雷射粒徑分析儀測量粒徑大小，結果發現微乳液製備最佳比例為SDS：大豆油 = 1：9 (v/v)，溫度控制於75℃，其乳液粒徑為140 nm。實際比較微乳液與SDS溶液的脫附效率，發現微乳液的去除效率比單一的SDS溶液多出了3.5 ~ 4.5倍。探討污染物的濃度，是否會影響微乳液的脫附情況，發現隨著污染物濃度從100 ppm上升至500 ppm時，其脫附率從49% 增加到91%，最後藉由微乳液製備時間1天和7天的有效期限來說明微乳液是否會因為製作完成時間過久而導致脫附效率從91% 降低至69%。另一方面，探討微乳液再生的可能性，先用等溫吸附模式來觀察活性碳能否吸附微乳液中的PAHs，之後在實際應用於經土壤脫附實驗後的微乳液，並再重複使用。再生的微乳液之脫附率可達61%，造成脫附率下降的原因為再生的微乳液有殘留anthracene，進而影響對新污染土壤的脫附，若忽略殘留的anthracene，其脫附率與新鮮的微乳液相同。

關鍵字

多環芳香烴化合物 ； 土壤整治 ； 微乳液 ； 再生微乳液 ； 活性碳 ； 脫附效率

並列摘要

The micro-emulsified solvent(MES) prepared by adding soybean oil into anionic surfactant SDS (10 CMC) and the mixed surfactant were used to study the remediation of PAH contaminated soil. The stability of emulsified surfactant was investigated to avoid the stratification between water layer and emulsified droplets (micelles) by changing the ratio of oil to surfactant and the temperature. Mixture of two surfactants has been proved to be more efficiency than single surfactant for the desorption of hydrophobic contaminants from soil. Triton X-100 and SDS were mixed in different ratio to study the increase of the desorption efficiency (DE). The results show that increasing the time and temperature of sonification, the size of micelles decreased. The optimal condition of making micro-emulsified surfactant was at the ratio of oil to SDS (22.3 g/L) 1:9 (v/v) under 75℃, and the size of micelles formed was around 140 nm. Sonification time was also found to be a bottle-neck factor, and 40 min was decided. TheDE of MES was 3.5~4.5 folds of that only using SDS (10CMC) for anthracene contaminated soil at 500 ppm under the reaction time 48 h. The DE increases with the increasing of anthracene concentration sorbed in soil. If only Triton X-100 was used, the DE was 4.5% only. The age of MES resulted the decrease of the DE from 91% to 69% for 1day and 7 days, respectively. Regeneation of used MES reached 61% DE, the reason caused the decrease is due to the anthracene residual. In short, the EMS and mixed surfactant can greatly increase the DE of hydrophobic contaminant in soils.

並列關鍵字

polycyclic aromatic hydrocarbons ； soil remediation ； microemulsion ； regenerated microemulsion ； activated carbon ； desorption efficiency

參考文獻

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