What question did this study set out to answer?

To establish and validate direct and mediated electrochemical methods for quantifying the electron and proton transfer capacities and redox potentials of humic substances.

December 1, 2009Environmental Science & Technology

Novel Electrochemical Approach to Assess the Redox Properties of Humic Substances

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To establish and validate direct and mediated electrochemical methods for quantifying the electron and proton transfer capacities and redox potentials of humic substances.
Monitored direct electrochemical reduction (DER) of Leonardite Humic Acid (LHA) on glassy carbon electrodes using chronocoulometry and automated acid titration at pH 7.
Quantified redox states and electron-accepting capacities across 13 humic substances using mediated electrochemical reduction (MER) and mediated electrochemical oxidation (MEO) facilitated by organic radical mediators.
DER of LHA demonstrated an H+/e- transfer ratio of unity and shifted redox potential from Eh = +0.18 V to -0.23 V upon transfer of 822 µmol e- per gram of LHA.
Electron transfer to LHA was largely reversible through cyclic DER and O2-reoxidation, leaving only a minor fraction unoxidized due to an endergonic initial electron transfer to O2.
Electron-accepting capacities across 13 humic substances strongly correlated with aromaticity and carbon-to-hydrogen ratios, detecting capacities threefold higher than historical approaches.

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Implication

Electrochemical study reveals reversible electron transfer in humic substances, indicating quinone moieties drive environmental electron-exchange capacity.

Cite This Study

Aeschbacher et al. (2009) studied this question.

synapsesocial.com/papers/6a016f4fbd6301933f5c94f6 https://doi.org/10.1021/es902627p

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Implication

Electrochemical study reveals reversible electron transfer in humic substances, indicating quinone moieties drive environmental electron-exchange capacity.

Novel Electrochemical Approach to Assess the Redox Properties of Humic Substances

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Discussion

Implication

Cite This Study

Novel Electrochemical Approach to Assess the Redox Properties of Humic Substances

Key Points

Discussion

Implication

Cite This Study

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