本研究以碳酸-溶氧進料系統處理濃度為1.25 mM至5 mM亞鐵廢水並合成α-FeOOH。
於瓶杯實驗中發現，在無碳酸僅含溶氧的系統中，於酸性條件形成γ-FeOOH，而在鹼性環境則生成Fe3O4。在含碳酸曝氮氣系統中，因曝氣使得碳酸受氣提作用逸散，溶液也處於低溶氧狀態，產物先於酸性條件形成γ-FeOOH，後與溶液中未氧化的亞鐵反應，最終轉變為Fe3O4。在碳酸-溶氧共存的系統中，於弱酸性至中性(pH 6~7)環境下，生成α-FeOOH與γ-FeOOH混合物，而在鹼性環境中，同樣生成Fe3O4；而在探討[CO32-]/[Fe2+]莫爾比對系統的影響時，因瓶杯實驗係屬開放式系統，發現額外添加的碳酸會與大氣二氧化碳平衡而逸散，使得產物同樣為α-FeOOH與γ-FeOOH混合物。瓶杯實驗溶液中溶氧不足需3小時才能完全氧化亞鐵，另ORP電位可做為亞鐵氧化反應的指標性因子。
　　後續利用Fenton流體化床(FBR-Fenton)均質化顆粒處理亞鐵廢水並生成鐵氧化物，於碳酸-溶氧進料系統中發現，pHeff大於6時，鐵去除率與結晶率，分別達到96.7%及65.9%，顯示此系統應操作在pHeff 6以上。在較低截面負荷(小於3.21 kg-Fe/m2•h)時，鐵去除率可達80~90%，而結晶率則介於50~65%，當截面負荷上升，因溶氧的不足，鐵去除率與結晶率大幅降低至31.7%與20.4%，故系統最高負荷約在3.21 kg-Fe/m2•h。由於碳酸-溶氧進料系統溶氧不足，故接下來在碳酸溶夜中加入氧化劑過氧化氫，形成碳酸-過氧化氫進料系統，研究發現，故當[H2O2]/[Fe2+]莫爾比提升至0.5~0.9時，鐵去除率與結晶率分別達98.5%及78.5%。碳酸-過氧化氫進料系統截面負荷約在2.41 ~ 3.21 kg-Fe/m2•hr。比較上述兩個系統，碳酸-溶氧進料系統受限於溶液中溶氧供應不足，鐵去除率遠低於碳酸-過氧化氫進料系統，但碳酸-過氧化氫進料系統因沉澱驅動力過強，致使鐵結晶率低於碳酸-溶氧進料系統。

This study aimed to treat the wastewater with 1.25 mM to 5 mM of ferrous ions with carbonate and oxygen to form goethite.
Jar-test results showed that γ-FeOOH was formed at acidic pH, whereas Fe3O4 was generated at basic pH in the absence of carbonate ions. γ-FeOOH was produced at the beginning and then reacted with ferrous ions to form Fe3O4 with the aeration of nitrogen. A mixture of α-FeOOH and γ-FeOOH was synthesized at weakly acid pH in the presence of carbonate and dissolved oxygen. Emission of carbon dioxide and insufficiency of dissolved oxygen are main obstacles to completely oxidize ferrous ions. Besides, ORP could be an indicator of the extent of ferrous oxidization.
In FBHG, when pHeff was higher than 6, the iron removal and iron crystallization ratio in carbonate-dissolved oxygen system could achieve 96.7% and 65.9%, respectively. With 3.21 kg-Fe/m2•h of actual surface loading, the iron removal and iron crystallization ratio could reach 80~90% and 50~65%, respectively. In order to provide sufficient oxidant, hydrogen peroxide was applied in this study. The results indicated that when [H2O2]/[Fe2+] increased from 0.5 to 0.9, the iron removal and iron crystallization ratio could achieve 98.5% and 78.5%, respectively. In carbonate-hydrogen peroxide system, the actual surface loading was in the range of 2.41~3.21 kg-Fe/m2•hr. The iron removal of carbonate-hydrogen peroxide system was higher owing to efficient oxidation of ferrous ions, while iron crystallization ratio of carbonate-dissolved oxygen system was higher because of intense driving force for precipitation.

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