TY - JOUR
T1 - Assessing redox properties of standard humic substances
AU - Rakshit, S.
AU - Sarkar, D.
N1 - Publisher Copyright:
© 2017, Islamic Azad University (IAU).
PY - 2017/7/1
Y1 - 2017/7/1
N2 - Redox properties of humic substances (HS) control important biogeochemical processes. Thus, accurate estimation of redox properties of HS is essential. However, there is no general consensus regarding the best available measurement method of HS redox properties. In this study, we compared several common HS redox property measurement methods using anthraquinone-2,6-disulfonate (AQDS) as model compound, and standard Elliot soil humic acid (1S102H, ESHA), reference Pahokee peat (1R103H, PPHA), and Suwannee River natural organic matter (1R101N, SRNOM) as representative HS. We found that the H2/Pd reduction method followed by incubation with ferric citrate (FeCit) reagent was incomplete, and the H2/Pd reduction method followed by incubation with potassium ferricyanide (K3Fe(CN)6) was insensitive. Stannous chloride (SnCl2) reduction followed by titration of excess stannous (Sn2+) by potassium dichromate (K2Cr2O7) was found to be most accurate. These findings will help in future investigations on detailed characterizations of functional groups of HS responsible for oxidation/reduction reactions.
AB - Redox properties of humic substances (HS) control important biogeochemical processes. Thus, accurate estimation of redox properties of HS is essential. However, there is no general consensus regarding the best available measurement method of HS redox properties. In this study, we compared several common HS redox property measurement methods using anthraquinone-2,6-disulfonate (AQDS) as model compound, and standard Elliot soil humic acid (1S102H, ESHA), reference Pahokee peat (1R103H, PPHA), and Suwannee River natural organic matter (1R101N, SRNOM) as representative HS. We found that the H2/Pd reduction method followed by incubation with ferric citrate (FeCit) reagent was incomplete, and the H2/Pd reduction method followed by incubation with potassium ferricyanide (K3Fe(CN)6) was insensitive. Stannous chloride (SnCl2) reduction followed by titration of excess stannous (Sn2+) by potassium dichromate (K2Cr2O7) was found to be most accurate. These findings will help in future investigations on detailed characterizations of functional groups of HS responsible for oxidation/reduction reactions.
KW - Electron shuttle
KW - Humics
KW - Quinone
KW - Redox
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U2 - 10.1007/s13762-017-1263-9
DO - 10.1007/s13762-017-1263-9
M3 - Article
AN - SCOPUS:85020544778
SN - 1735-1472
VL - 14
SP - 1497
EP - 1504
JO - International Journal of Environmental Science and Technology
JF - International Journal of Environmental Science and Technology
IS - 7
ER -