scholarly journals Microbial reduction of Fe(III)-bearing clay minerals in the presence of humic acids

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Guangfei Liu ◽  
Shuang Qiu ◽  
Baiqing Liu ◽  
Yiying Pu ◽  
Zhanming Gao ◽  
...  
Keyword(s):  
Clay Minerals ◽  
Humic Acids ◽  
Microbial Reduction

scholarly journals Insight to Microbial Fe(III) Reduction Mediated by Redox-Active Humic Acids with Varied Redox Potentials

2021 ◽  
Vol 18 (13) ◽  
pp. 6807
Author(s):  
Jingtao Duan ◽  
Zhiyuan Xu ◽  
Zhen Yang ◽  
Jie Jiang
Keyword(s):  
Molecular Weight ◽  
Electron Transfer ◽  
Humic Acids ◽  
Weight Fraction ◽  
Electrochemical Analysis ◽  
Microbial Reduction ◽  
Redox Potentials ◽  
Groundwater Environment ◽  
Redox Active ◽  
Different Molecular Weight

Redox-active humic acids (HA) are ubiquitous in terrestrial and aquatic systems and are involved in numerous electron transfer reactions affecting biogeochemical processes and fates of pollutants in soil environments. Redox-active contaminants are trapped in soil micropores (<2 nm) that have limited access to microbes and HA. Therefore, the contaminants whose molecular structure and properties are not damaged accumulate in the soil micropores and become potential pollution sources. Electron transfer capacities (ETC) of HA reflecting redox activities of low molecular weight fraction (LMWF, <2.5) HA can be detected by an electrochemical method, which is related to redox potentials (Eh) in soil and aquatic environments. Nevertheless, electron accepting capacities (EAC) and electron donating capacities (EDC) of these LMWF HA at different Eh are still unknown. EDC and EAC of different molecular weight HA at different Eh were analyzed using electrochemical methods. EAC of LMWF at −0.59 V was 12 times higher than that at −0.49 V, while EAC increased to 2.6 times when the Eh decreased from −0.59 V to −0.69 V. Afterward, LMWF can act as a shuttle to stimulate microbial Fe(III) reduction processes in microbial reduction experiments. Additionally, EAC by electrochemical analysis at a range of −0.49–−0.59 V was comparable to total calculated ETC of different molecular weight fractions of HA by microbial reduction. Therefore, it is indicated that redox-active functional groups that can be reduced at Eh range of −0.49–−0.59 are available to microbial reduction. This finding contributes to a novel perspective in the protection and remediation of the groundwater environment in the biogeochemistry process.

Thermodynamics of Clay Minerals-Humic Acids Interaction

2017 ◽  
Vol 23 (6) ◽  
pp. 5859-5861 ◽  
Author(s):  
Vincenzo Leone ◽  
Pasquale Iovino ◽  
Stefano Salvestrini ◽  
Elio Coppola ◽  
Sante Capasso
Keyword(s):  
Clay Minerals ◽  
Humic Acids

Fractionation of humic acids by clay minerals assayed by 13C-NMR spectroscopy

2010 ◽  
Vol 434 (1) ◽  
pp. 341-346 ◽  
Author(s):  
T. V. Alekseeva ◽  
B. N. Zolotareva ◽  
Yu. G. Kolyagin
Keyword(s):  
Nmr Spectroscopy ◽  
Clay Minerals ◽  
Humic Acids ◽  
13C Nmr ◽  
13C Nmr Spectroscopy

scholarly journals Haplic chernozems humus condition of Western Bug and Styr terraced landscapes

2016 ◽  
pp. 296-308
Author(s):  
Pavlo Papish ◽  
Halyna Ivanyuk ◽  
Ihor Papish
Keyword(s):  
Organic Matter ◽  
Clay Minerals ◽  
Optical Density ◽  
Humic Acids ◽  
Fulvic Acids ◽  
Soil Thickness ◽  
Humus Profile ◽  
Haplic Chernozems ◽  
High Degree ◽  
Very High

Volyn Upland Haplic Chernozems are distributed mainly on the terrace landscapes of the Western Bug and the Styr and their tributaries (Chornohuzka, Luha, Lypa). Most of these soils are old ploughlands that have experienced various types of degradation. Haplic Chernozems are low-humus soils and they have low storages of humus substance in the 20 cm arable layer and middle storages of humus in 100 cm soil thickness. There is correlation of C humic acids to C fulvic acids within 1.2–3.3 in the humus profile. Among the various fractions of humic substances the 2nd fraction associated to Calcium dominates. A content of “free” humic acids (1rst fraction) is very low and the amount of humin is low. The optical density of humic acids ( 0,001% НА Е1 cm, 465 nm ) are high and very high. The organic matter of Volyn Upland Haplic Chernozems has some regional peculiarities. First, it caused by topographical conditions of its formation and evolution in the Holocene. Chernozems of the 1st terrace of the River Western Bug are extremely deep. They have progressive-accumulative type of humus distribution in profile, humate type of humus in upper 100 cm layer, a very high degree of organic matter humification and the same content of humic fraction associated to Calcium and lowmiddle content of 3rd fraction associated to clay minerals. The molecules of humic acids in the humus horizon of Chernozems of the 1rst terrace are better structured that indicates the older age of humus in these soils. Chernozems of the 2nd terrace above the floodplain of the River Styr are middle-deep soils. They are characterised by the regressive-accumulative type of humus distribution in profile, humate-fulvate type of humus and very high degree of organic matter humification only in 25–50 cm layer. The content of fractions associated to Calcium and clay minerals is predominantly high. Key words: Haplic Chernozems, humus, humic acids, fulvic acids, optical density, humus condition.

Sorption of L -methionine-sulphoximine on humic acids and clay minerals

2000 ◽  
Vol 31 (3-4) ◽  
pp. 356-359 ◽  
Author(s):  
A. Gelsomino ◽  
G. Cacco ◽  
P. Nannipieri
Keyword(s):  
Clay Minerals ◽  
Humic Acids ◽  
Methionine Sulphoximine

scholarly journals Redox Structures of Humic Acids Derived From Different Sediments and Their Effects on Microbial Reduction Reactions

2018 ◽  
Vol 9 ◽  
Author(s):  
Ning Zhang ◽  
Dong-Dong Zhang ◽  
Hong-Da Ji ◽  
Xin-Wei Yu ◽  
Zhi-Chao Zhang ◽  
...  
Keyword(s):  
Humic Acids ◽  
Microbial Reduction ◽  
Reduction Reactions
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