Iron Isotope Fractionation During Reduction of Fe(III) to Fe(II)
The natural reduction of Fe(III) to Fe(II) in the oceans is simulated in the lab in three very different sorts of experiments. First, simply taking the Fe(III) bound to an organic ligand into the direct sunlight leads to photochemical reduction of Fe(III) to Fe(II) by ligand-to-metal charge transfer. Secondly, we can chemically reduce Fe(III) to Fe(II) using a reducing agent, such as hydroxylamine hydrochloride. Thirdly, we can reduce Fe(III) to Fe(II) electrochemically by applying a voltage to a rotating disk electrode. Interestingly, our preliminary data indicates that each of these three methods has a very different isotope effect, leading to Fe(II) with a very different isotopic ratio.
