Nitrogen K-edge X-ray adsorption near-edge structure spectroscopy of chemically adsorbed ammonia gas on clay minerals and the 15N/14N-nitrogen isotopic fractionation

Haruna Sugahara; Toshihiro Yoshimura; Yusuke Tamenori; Yoshinori Takano; Nanako O Ogawa; Yoshito Chikaraishi; Naohiko Ohkouchi

doi:10.1007/s44211-023-00503-5

Nitrogen K-edge X-ray adsorption near-edge structure spectroscopy of chemically adsorbed ammonia gas on clay minerals and the ¹⁵N/¹⁴N-nitrogen isotopic fractionation

Anal Sci. 2024 Apr;40(4):781-789. doi: 10.1007/s44211-023-00503-5. Epub 2024 Feb 5.

Authors

Haruna Sugahara^{1

2}, Toshihiro Yoshimura³, Yusuke Tamenori^{4

5}, Yoshinori Takano³, Nanako O Ogawa³, Yoshito Chikaraishi^{3

6}, Naohiko Ohkouchi³

Affiliations

¹ Biogeochemistry Research Center (BGC), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Natsushima, Yokosuka, Kanagawa, 237-0061, Japan. sugahara.haruna@jaxa.jp.
² Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), 3-1-1 Yoshinodai, Chuo-Ku, Sagamihara, Kanagawa, 252-5210, Japan. sugahara.haruna@jaxa.jp.
³ Biogeochemistry Research Center (BGC), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Natsushima, Yokosuka, Kanagawa, 237-0061, Japan.
⁴ Japan Synchrotron Radiation Research Institute, SPring-8, 1-1-1 Kouto, Sayo, Hyogo, 679-5198, Japan.
⁵ Organization for Research Promotion, Tokyo Metropolitan University, Minami-Osawa, 1-1, Hachioji, Tokyo, 192-0397, Japan.
⁶ Institute of Low Temperature Science, Hokkaido University, Sapporo, Hokkaido, 060-0819, Japan.

Abstract

Ammonia (NH₃) is a simple and essential nitrogen carrier in the universe. Its adsorption on mineral surfaces is an important step in the synthesis of nitrogenous organic molecules in extraterrestrial environments. The nitrogen isotopic ratios provide a useful tool for understanding the formation processes of N-bearing molecules. In this study, adsorption experiments were conducted using gaseous NH₃ and representative clay minerals. The strongly adsorbed NH₃ was ¹⁵N-enriched in a state of chemical equilibrium between the adsorption and desorption on the siliceous host surface. The nitrogen K-edge X-ray adsorption near-edge structure spectroscopy study revealed that these initial ammonia gases were chemically adsorbed as ammonium ions (NH₄⁺) on clay minerals.

Keywords: Adsorption; Ammonia; Clay mineral; Nitrogen isotopic fractionation; XANES.

Abstract

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