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|出版社:||國立中興大學工學院;Airiti Press Inc.|
|摘要:||Oil and grease are widely used in industrial and domestic activities. Hence they exist in wastewaters and bodies, such as river water and ground water. One of the standard determination methods for oil and grease in polluted waters is a gravimetric procedure based on a Soxhlet extraction with 1,1,2-trichloro-1,2,2-trifluroethane or n-hexane. However, the Soxhelt-extracton procedure is time-comsuming. The aim of this work was to carry out a revision of the experimental conditions for the determination of oil and grease by employing a microwave-assisted extraction followed by gravimetry.
The main factors affecting extraction efficiency include microwave irradiation power, microwave irradiation time and the volume of extraction solvent. After an oil (about 0.3 g) was directly added on filter papers, preliminary results by using a focused microwave extractor with 40 mL hexane/acetone (v:v=1:1) provided quantitative recoveries (86-94%) when an irradiation time of 10 min and an exit power of 62.5W were employed. The proposed method was evaluated by using a meat-processing wastewater, an electro-plating wastewater, a river water and a near-shore seawater after filtration. Real samples spiked with different types of oils were examined, and the recoveries were consistent with those based on conventional Soxhlet extraction method. Substantial reduction of analysis time is achieved and less amount of extracting solvent is required by use of the proposed method.|
河川、地下水等自然水體遭受油脂污染後，一般採用索氏萃取法(Soxhlet extraction method)配合稱重法或紅外光法測得水中的油脂濃度。依據萃取-稱重檢測方法的標準程序，僅萃取步驟即需要4小時。由於微波加熱法可以大幅縮短萃取步驟所需的時間(由4小時減至10分鐘)和減少萃取試劑的使用量(由250 mL減mL)， 本研究使用開放焦式微波加熱法來取代傳統的索氏萃取法。由研究結果得知，直接將不同種類油脂(約0.3g)滴加在濾紙上，捲放圓筒濾紙中，放入微波萃取管，加入40 mL正己烷/丙酮混合萃取液，使用25%(62.5 W)的功率，萃取10分鐘，可得86-94%的回收率。另外針肉品市場廢水、電板業廢水、梧棲港海水、後龍溪溪水以及旱溪溪水等真實樣品，各取約一升水樣先經過濾截留油脂於濾紙後，將濾紙捲放於圓筒濾紙中，再經烘乾去除水分後，放入微波萃取管，依上述相同的條件萃取所得的結果，只有肉品市場廢水測得油脂量為5-10 mg/L，其餘水樣均低於方法偵測極限(5 mg/L)。當以真實水樣為基質，添加試驗萃取一次的結果，回收率為75-95%。若萃取兩次時，回收率可達84-104%。由以上結果顯示，微波萃取法確可取代索氏萃取法。
|Appears in Collections:||第14卷 第1期|
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