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  • Electron exchange capacity of pyrogenic dissolved organic matter (pyDOM): complementarity of square-wave voltammetry in DMSO and mediated chronoamperometry in water
Title: Electron exchange capacity of pyrogenic dissolved organic matter (pyDOM): complementarity of square-wave voltammetry in DMSO and mediated chronoamperometry in water
Pyrogenic dissolved organic matter (pyDOM) is derived from black carbon, which is important in the global carbon cycle and other biogeochemical redox processes. The electron-exchange capacity (EEC) of pyDOM has been characterized in water using mediated chronoamperometry (MCA), which gives precise results under specific operational conditions, but the broader significance of these EECs is less clear. In this study, we described a novel but complementary electrochemical approach to quantify EECs of pyDOM without mediation using square-wave voltammetry (SWV) in dimethyl sulfoxide (DMSO). Using both the SWV and MCA methods, we determined EECs for 10 pyDOMs, 6 natural organic matter (NOM) samples, and 2 model quinones. The two methods gave similar EECs for model quinones, but SWV gave larger EECs than MCA for NOM and pyDOM (by several-fold and 1–2 orders of magnitude, respectively). The differences in the EECs obtained by SWV and MCA likely are due to multiple factors, including the potential range of electrons sampled, kinetics of electron transfer from (macro)molecular structures, and coupling of electron and proton transfer steps. Comparison of the results obtained by these two methods should provide new insights into important environmental processes such as carbon-cycling, wildfire recovery, and contaminant mitigation using carbon-based amendments.  more » « less
Award ID(s):
1752220
PAR ID:
10413970
Author(s) / Creator(s):
; ; ; ;
Date Published:
Journal Name:
Environmental Science: Processes & Impacts
Volume:
25
Issue:
4
ISSN:
2050-7887
Page Range / eLocation ID:
767 to 780
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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