Density functional theory calculations of nitrogen and oxygen equilibrium isotope fractionations in NO3--NO2--H2O aqueous system reveal inverse kinetic isotope effects during nitrite oxidation

doi:10.1016/j.apgeochem.2022.105265

CORC > 力学研究所 > 中国科学院力学研究所 > 高温气体动力学国家重点实验室

	Density functional theory calculations of nitrogen and oxygen equilibrium isotope fractionations in NO3--NO2--H2O aqueous system reveal inverse kinetic isotope effects during nitrite oxidation
	He, Yuyang 2,3; Li, Long 1
刊名	APPLIED GEOCHEMISTRY
	2022-04-01
卷号	139 页码:11
关键词	Reduced partition function ratio Nitrate reduction Water-droplet model Solvent effect Inverse kinetic isotope effect
ISSN号	0883-2927
DOI	10.1016/j.apgeochem.2022.105265
通讯作者	He, Yuyang(yhe@mail.iggcas.ac.cn)
英文摘要	Nitrate and nitrite play key roles in the nitrogen cycle on Earth's surface. The isotope fractionation during nitrate reduction on enzymatic level involves multiple steps, including transfer of free NO3- to the activate site on nitrate reductase and NO2 equilibration with ambient water. However, the isotope fractionation factors of 15N and O-18 among NO3-, NO2-, and H2O molecules in aqueous phases are poorly constrained. It strongly impedes the understanding of the involved processes and using stable isotopes to quantitatively examine the biogeochemical nitrogen cycle. In this contribution, we employ the density functional theory method with the UreyBigeleisen-Goeppert-Mayer model to predict the nitrogen and oxygen equilibrium isotope fractionation factors of NO3-, NO2-, and H2O molecules in gaseous and aqueous phases. Our calculation results show that the solvent effect has a large influence on equilibrium isotope fractionation for oxygen in water (+10.1 parts per thousand between liquid and vapor water at 25 degrees C), which is different to the little solvent effects on both oxygen and nitrogen in nitrate and nitrite. The calculated temperature-dependent equilibrium isotope fractionations between nitrogen of NO3- and NO2, and oxygen of H2O and NO2 are consistent with previous laboratory experiments. Our results confirm that the oxygen equilibrium isotope fractionations between NO3 and NO2 should be +9.4 parts per thousand at 25 degrees C. Integrating the new results and previously reported kinetic isotope effects of nitrate reduction, we demonstrate inverse kinetic isotope effects for both nitrogen (+15.4 parts per thousand) and oxygen (+5.2 parts per thousand) during nitrite oxidation, which falls in the range of previous experiments. The new results enable us to use both nitrogen and oxygen isotopes as a bonded isotope tool to quantitatively assess the nitrogen cycle in low-temperature environments.
资助项目	National Science Foundation of China[4217030170] ; National Science Foundation of China[42150202] ; China Postdoctoral Science Foundation[2019M660811] ; pre-research project on Civil Aerospace Technologies of China National Space Administration[D020203]
WOS关键词	THEORETICAL CALCULATION ; NITRATE REDUCTION ; WATER MOLECULE ; CARBON-DIOXIDE ; LIQUID WATER ; AB-INITIO ; EXCHANGE ; DIFFRACTION ; MECHANISMS ; RATIOS
WOS研究方向	Geochemistry & Geophysics
语种	英语
WOS记录号	WOS:000799844300006
资助机构	National Science Foundation of China ; China Postdoctoral Science Foundation ; pre-research project on Civil Aerospace Technologies of China National Space Administration
内容类型	期刊论文
源URL	[http://dspace.imech.ac.cn/handle/311007/89588]
专题	力学研究所_高温气体动力学国家重点实验室
通讯作者	He, Yuyang
作者单位	1.Univ Alberta, Dept Earth & Atmospher Sci, Edmonton, AB T6G 2E3, Canada 2.Chinese Acad Sci, Inst Mech, State Key Lab High Temp Gas Dynam, Beijing, Peoples R China 3.Chinese Acad Sci, Inst Geol & Geophys, Key Lab Earth & Planetary Phys, Beijing, Peoples R China
推荐引用方式 GB/T 7714	He, Yuyang,Li, Long. Density functional theory calculations of nitrogen and oxygen equilibrium isotope fractionations in NO3--NO2--H2O aqueous system reveal inverse kinetic isotope effects during nitrite oxidation[J]. APPLIED GEOCHEMISTRY,2022,139:11.
APA	He, Yuyang,&Li, Long.(2022).Density functional theory calculations of nitrogen and oxygen equilibrium isotope fractionations in NO3--NO2--H2O aqueous system reveal inverse kinetic isotope effects during nitrite oxidation.APPLIED GEOCHEMISTRY,139,11.
MLA	He, Yuyang,et al."Density functional theory calculations of nitrogen and oxygen equilibrium isotope fractionations in NO3--NO2--H2O aqueous system reveal inverse kinetic isotope effects during nitrite oxidation".APPLIED GEOCHEMISTRY 139(2022):11.