不同曝氣頻率對薄膜表面積垢之影響

懸浮態TiO2反應器中，催化劑的溢流是其主要缺點。結合薄膜過濾可有效分離催化劑與污水，克服催化劑溢流的問題。但隨之而來的積垢卻是另一影響其功能正常運行的問題。反應槽曝氣不僅能藉由氣泡上升產生的剪力刮除薄膜積垢，且能作為水中溶氧之來源，並維持TiO2顆粒於水中懸浮之狀況。本研究以UV/TiO2反應器結合薄膜過濾系統進行操作，主要以改變薄膜通量(32LMH、64LMH)及曝氣頻率(1:2、1:4、1:9、2:8)來對PAN及PVDF兩種高分子薄膜進行評估氣泡刷洗薄膜積垢及維持TiO2顆粒懸浮之能力。結果顯示，操作在32LMH通量下，曝氣頻率的改變對於積垢產生及減緩TiO2顆粒懸浮之影響不大。PVDF相較於PAN之薄膜阻抗較低。而在64LMH通量下，改變曝氣頻率可以有效減緩薄膜積垢產生，並維持溶液中TiO2顆粒懸浮情況，以1:2試程之結果最好。PAN薄膜孔洞較緻密，積垢主要形成於薄膜表面，積垢量亦較大。PVDF薄膜孔洞較大，部份積垢會阻塞在孔洞中，但積垢產生情形較PAN來的不明顯。而由經濟成本考量與各試程效率差異比較顯示，PVDF薄膜下1:2試程會比較適合。

關鍵字

PVDF ； UV/TiO2-membrane ；積垢阻抗； PAN ；曝氣頻率

並列摘要

The major limitation of suspended type UV/TiO2 reactor is the difficulty in separating TiO2 particles from disinfected water. Coupling the reactor with membrane process can effectively overcome this problem. However, TiO2 particles will block can cause membrane fouling. Aeration can produce shear force to clean the fouling and produce DO. In this study, membrane type (PAN and PVDF), control flux (32 and 64 LMH) and aeration frequency (1:2, 1:4, 1:9, and 2:8 ON/OFF) were studied to determine the parameter that minimized fouling and maintained good suspension. The results have shown that at 32 LMH, the aeration frequency is not important, and that PVDF has lower membrane resistance than PAN. Changing aeration frequency can effectively reduce the fouling and maintain the TiO2 suspension at 64 LMH. PAN is denser than PVDF in membrane surface. PAN has greater cake resistance than PVDF. PVDF have bigger pore size, and thus less pore-blocking occurred than PAN. Taking the economic costs into account, PVDF with 1:2 aeration frequency would be more appropriate for photoreactors.

並列關鍵字

PVDF ； PAN ； aeration frequency ； fouling ； UV/TiO2-membrane

參考文獻

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國際替代計量

不同曝氣頻率對薄膜表面積垢之影響

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