|摘要: ||多環芳香烴化合物(PAHs)具有低水溶性及低揮發性之特性，本研究嘗試結合鹼活化過硫酸鹽(氧化性破壞)及泡沫淋洗(物理性移除)兩項技術，以氧化性泡沫整治受PAHs (例如萘)污染之未飽和含水層土壤進行評估。實驗首先針對鹼性過硫酸鹽泡沫產生之可行性及泡沫特性進行探討，藉由不同濃度之界面活性劑(Sodium dodecylsulfate, SDS)搭配固定濃度之氧化劑(Sodium persulfate, SPS)配比產生泡沫，結果顯示以1.5% SDS/0.1 M SPS/0.1 M NaOH混合溶液可穩定生成具氧化性之泡沫，其所生成之泡沫其品質高達99.8%、泡沫穩定性為0.8 hr。由增溶試驗結果指出，相較於萘之水中飽和溶解度，上述混合溶液對萘增溶後之濃度可提高至16.6倍，此外SPS及NaOH添加下對萘之增溶濃度無顯著影響。接續由批次降解試驗的結果得知，以鹼活化過硫酸鹽氧化方式可於24 hr內完全降解水溶液中萘(26.3 mg/L)，但SDS之存在下會減緩其降解速率。|
Polycyclic aromatic hydrocarbons (PAHs) have the characteristics such as low solubility and low volatilization. This study was conducted to develop an oxidative foam flushing technology, which combines the benefits of alkaline activated persulfate and surfactant foam flushing for the treatment of PAHs (e.g., naphthalene) contaminated soils.
The feasibility of producing alkaline activated persulfate foam with the mixed solution which contains surfactant (Sodium dodecylsulfate, SDS, at various concentration levels) and oxidant (Sodium persulfate, SPS, at one concentration level) and their characteristics were examined. The results showed 1.5% SDS/0.1 M SPS/0.1 M NaOH mixed solution can be employed to generate stable oxidative foam, with characteristics of foam quality of 99.8% and stability of 0.8 hr. In the solubilization test, the solubility of naphthalene increased about 16.6 folds in solution with the above mentioned composition than the naphthalene aqueous saturated solubility. Furthermore, it was observed that the solubilization of naphthalene was not affected by addition of SPS or NaOH. Naphthalene in the aqueous phase (26.3 mg/L) can be completely degraded in 24 hr with alkaline activated persulfate system. However, the presence of SDS would decrease the degradation rate of naphthalene.
The results of soil column experiments showed that the removal of naphthalene was about 94.0% by oxidative foam flushing. 41.4% of naphthalene was removed by liquid while the remaining portion of naphthalene removal was induced in gaseous phase. Additional soil column experiments spiked with anthracene, which has a lower volatility was conducted.
Experimental results showed the removal of anthracene was about 68.0% in which the percentages of anthracene removal in liquid and suspension/sediments were 38.4% and 14.9%, respectively. In addition, through mass balance calculation, it was found that 14.6% of anthracene was destroyed by oxidation. In conclusion, the oxidative foam flushing would function both physical removal and chemically destroy PAHs and therefore, exhibits the potential for remediating PAHs contaminated soils.