The Department of Soil and Water Sciences, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
J Hazard Mater. 2009 Nov 15;171(1-3):704-9. doi: 10.1016/j.jhazmat.2009.06.057. Epub 2009 Jun 21.
The processes of iron oxidation in an electroflocculation cell were investigated for a pH range of 5-9 and electric currents of 0.05-0.4A (equivalent current densities of 8.6-69 A/m(2)). At all pH values and electric currents investigated, it was demonstrated and proven that for all practical purposes, the form of iron that dissolves from the anode is Fe(2+) (ferrous). The difference between the amount of theoretical dissolution as calculated by Faraday's law and the amount of observed dissolved iron ions may indicate two phenomena in electrochemical cells. The first is possible dissolution of the anode even without the operation of an electric current; this led to higher theoretical dissolution rates at lower pH. The second is the participation of some of the electrons of the electric current in reactions other than anode dissolution which led to lower theoretical dissolution rates at higher pH. Those other reactions did not lead to an increase in the local oxidation saturation level near the anode and did not affect iron-oxidation rates in the electroflocculation processes. The oxidation rates of the dissolved Fe(2+) (ferrous) to Fe(3+) (ferric) ions in electroflocculation processes were strongly dependent on the pH and were similar to the known oxidation rates of iron in non-electrochemical cells.
研究了 pH 值范围为 5-9 和电流 0.05-0.4A（等效电流密度为 8.6-69 A/m²）的电絮凝池中铁的氧化过程。在所有研究的 pH 值和电流下，都证明了从阳极溶解的铁的形式为 Fe(2+)（亚铁）。法拉第定律计算的理论溶解量与观察到的溶解铁离子量之间的差异可能表明电化学电池中存在两种现象。第一种是即使没有电流作用，阳极也可能发生溶解，这导致在较低 pH 值下理论溶解速率更高。第二种是电流的一些电子参与了除阳极溶解以外的反应，这导致在较高 pH 值下理论溶解速率较低。这些其他反应不会导致阳极附近的局部氧化饱和度增加，也不会影响电絮凝过程中的铁氧化速率。溶解的 Fe(2+)（亚铁）在电絮凝过程中氧化为 Fe(3+)（铁）离子的速率强烈依赖于 pH 值，并且与非电化学电池中铁的已知氧化速率相似。
