超音波輔助超濾膜清洗程序

Ultrasound Assisted Ultrafiltration membrane Cleaning Process

林尚賢(Shan-Shian Lin)

指導教授 ： 林正芳

國立臺灣大學/工學院/環境工程學研究所/碩士(2007年)

https://doi.org/10.6342/NTU.2007.10022

摘要

超音波輔助薄膜過濾/清洗程序，用來預防及清除超濾膜過濾溶解性有機物(腐質酸)所造成之積垢。研究應用20 kHz之低頻聚焦式超音波直接發射於有機膜面輔助薄膜過濾。以間歇式之操作觀察在外加及不加超音波下對滲流量之影響。發現在低壓力操作下及使用較小孔徑薄膜能有較佳之滲流量表現。
超音波輔助清洗程序。20 kHz氣穴現象有更強的氣泡崩壞，能鬆脫積垢之吸附現象，使深入清除剝落表面及孔徑內阻塞之積垢。傳統水力及NaOH清洗程序通量回復率分別為20 %、62 %，以超音波輔助清洗程序滲流通量回復提升為97 %。比較之下能得到較佳的通量回復率。而以100 kD、30 kD、10 kD孔徑之薄膜其通量回復率分別為97 %、97 %、99 %。在重複4次過濾清洗下其產水效率及水質狀態並無太大改變。然而以間歇式操作下有利於減少能源消耗，並以SEM觀察其表面狀態，顯現應用超音波操作方式不會對薄膜表面產生破壞。

關鍵字

超音波輔助清洗程序 ； 超濾薄膜 ； 氣穴現象 ； 間歇式操作

並列摘要

The most concerned issue in membrane filtration process is membrane fouling that causes permeate flux decline, reduces operation period and increases operation cost. In this study, ultrasound (US) assisted filtration and cleaning process was applied for fouling prevention and cleaning in ultrafiltration (UF) systems fouled by humic acid. Low frequency (20 kHz) probe type ultrasound propagated on the top of flat-sheet polyethersulfone (PES) membrane. Flux measurement indicates that US assisted membrane filtration operated at lower pressure and using smaller MWCO of membrane were effective for recovery of flux decline due to fouling.
Ultrasound assisted cleaning (UAC) process was applied in pulse mode. After fouling by humic acid,using different MWCO of fouled membranes treated in UAC process respectively. The results show that UAC process achieved high flux recovery (96~99 %), particularly for smaller MWCO of membrane. The data results suggest cavitation bubbles collapse phenomena, which can easily ensues fragmentation or abrasion on surface fouling. Operation was re-iterated 4 times on membrane reuse experiment, which performed in terms of quantity (flux recovery) and quality (TOC rejection rate). The result was barely changing in quantity and quality. Operating at high pressure, some damages were observed by SEM images. However, no damage to the membrane was observed.

並列關鍵字

Ultrasound assisted cleaning process ； Ultrafiltration ； Cavitation

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