科研之友
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摘要
Incomplete oxidation of Fe(II) species released from the anode to Fe(III) may impede iron electrocoagulation processes conducted under low dissolved oxygen and/or pH <7 conditions, accompanied by the typically high buffering capacity of wastewater. This paper introduces a new approach to overcome this drawback by applying a second electrochemical cell (Ti/RuO(2) anode and Ti cathode) to be operated in parallel to the electrocoagulation cell. The second unit oxidizes Cl(-) ions invariably present in the water to HOC, which is capable of oxidizing Fe(II) species at a high rate, irrespective of pH or O(2(aq)) concentration. An electrolytic cell with a Ti/RuO(2) anode and Ti cathode was shown to successively operate in parallel to a sacrificial electrocoagulation cell (Fe anode and Ti cathode) to attain complete Fe(II) conversion to Fe(III) under low-pH conditions, in which, in the absence of the 2nd cell, unwanted Fe(II) species would have dominated the dissolved iron species. Current efficiency for Cl(2) production was 12.4% and 45.7% at 200 and 1000 mg Cl/l, respectively. Under three practical conditions (pH 6, (Cl(-)] = 200 mg/l; pH 6, [Cl(-)] =400 mg/l; pH 5, [Cl(-)] = 600 mg/l) the power demand of the combined system was 25.29, 12.7 and 8.1 kWh/kg Fe(III)(produced), respectively, suggesting that the presented approach is competitive at [Cl(-)] > similar to 600 mg/l.
- 出版日期2010-11-15
