六價鐵為一種具有強氧化力與無機混凝性的新型淨水氧化劑，本研究以含鐵量高的廢棄污泥為原料，利用濕式氧化法進行合成六價鐵。由於實場污泥合成六價鐵易受其他成分影響，因此利用Fe(OH)3模擬實場污泥之主要成分進行其他成份做添加試驗，探討不同含量的錳離子、氧化鐵、二氧化錳對六價鐵製備之影響。
實驗結果顯示，濃度1.0M的HNO3在酸洗過程中可溶出最大量的鐵，在Fe(OH)3添加試驗中，以純Fe(OH)3製備六價鐵產量並不高，額外添加適量的二氧化錳與錳離子成分對六價鐵的產量有加成作用，但氧化鐵的成分影響較不顯著。綜合言之實場污泥製備六價鐵的產量高於純Fe(OH)3合成六價鐵的產量，污泥中其他成分之加成作用使得六價鐵產量提升。 The synthesis of ferrate (FeO4-2) from field waste sludge using the wet oxidation process was investigated and evaluated. Ferrate as an oxidant is now being considered as one of the new powerful oxidizing and coagulating agent can be synthesized from Fe(III) under alkaline conditions. Simulated sludge was first synthesized using analytical grade FeCl3 and NaOH to yield Fe(OH)3. Nitric acid (HNO3) is used to leach out Fe (III) from Fe(OH)3 at different acid concentrations. The maximum amount of Fe (III) from the sample was obtained using 1.0 M HNO3.
The impact of the presence manganese ions (Mn+2), manganese oxide (MnO2) and Fe2O3 is also evaluated by injecting a known amount of the three substances to the simulated sludge sample. Results showed that the presence of MnO2 significantly enhance the yield of ferrate and no significant effect was observed in ferrate yield in the presence of Mn+2 ions.In addition,no significant improvement on ferrate yield was observed in the presence of Fe2O3.
Experiments on actual field waste sludge for the synthesis of ferrate showed a higher ferrate yield compare to the simulated sludge.The increased yield of ferrate from actual waste sludge can be attributed to the presence of other substance,such as Mn oxide and hydroxide.
