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Kinetics of Competitive Reduction of Nitrate and Iron Oxides by Aeromonas hydrophila HS01
Author(s) -
Liu Tongxu,
Zhang Wei,
Li Xiaomin,
Li Fangbai,
Zhang Wei,
Shen Weijun
Publication year - 2014
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2014.04.0164
Subject(s) - kinetics , hematite , chemistry , goethite , nitrate , cyclic voltammetry , inorganic chemistry , nuclear chemistry , environmental chemistry , mineralogy , electrochemistry , organic chemistry , electrode , physics , adsorption , quantum mechanics
While the interaction between NO 3 − and Fe reduction is well reported, it still lacks a detailed quantitative analysis of the properties and reactions responsible for the competitive reduction. In this study, the kinetics of the reduction of NO 3 − and Fe oxides by Aeromonas hydrophila HS01 were investigated in an artificial groundwater medium. The presence of Fe oxides showed an inhibitory effect on NO 3 − reduction to a varying extent, and vice versa, which was also evidenced by cyclic voltammetry analysis of Fe(II)/Fe(III). Higher Fe(III) availability and increased Fe oxide surface areas were more favorable for Fe reduction but resulted in a stronger inhibitory effect on NO 3 − reduction. The inhibitory effect also decreased with increased hematite crystallinity. Based on the kinetics and the elementary reactions, we established a kinetic model suggesting that direct biotic NO 3 − reduction by HS01 is the leading contribution, while the cell‐associated Fe(II) produced by HS01 also reduced NO 3 − but with a limited contribution because the reaction rates of NO 3 reduction by cell‐associated Fe(II) are lower than that of NO 3 − reduction by HS01. This detailed kinetics and modeling study provides useful information for understanding the interaction between NO 3 − and Fe reduction in various subsurface environments.