The Fenton reaction would be most useful for water treatment if it could be made catalytic in iron at circumneutral pH. In homogeneous aqueous solution with simple iron salts, such performance is prevented by the low solubility of Fe(III) above pH ~4 and the inherent slowness of the back-reduction of Fe3+ to Fe2+. One strategy for overcoming these limitations is to include a ligand of suitable structure. In an initial effort, we systematically investigated the Fe(III)-catalyzed Fenton oxidation of atrazine in water using picolinic acid (PICA) which serves as a bidentate ligand. The PICA catalytic system was highly active towards removal of atrazine at pH 5 - 6 in comparison to the PICA-absent system. The responsible reactive species is hydroxyl radical (HO) as demonstrated by EPR analysis and chemical quenching experiments. Importantly, PICA accelerated H2O2-mediated Fe(III) reduction, resulting in faster HO generation. These results are a first step in understanding the role of the ligand on iron reactivity in Fenton chemistry and could lead to improved homogeneous or heterogeneous catalytic systems.

Efficient Fenton oxidation of atrazine at circumneutral pH mediated by a complexing agent, picolinic acid

2019 Fall National Meeting

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