Abstract
Amorphous calcium carbonate (ACC) is a precursor of crystalline calcium carbonate; hence, its structural information at the atomic level is very important for controlling the morphology of crystalline calcium carbonate. In this study, we attempted to elucidate the process of Sr extraction from aqueous solution by using ACC for the purpose of removal of radioactive Sr from the contaminated water leaked after the Fukushima Daiichi nuclear accident. The pair distribution functions, g(r) obtained by X-ray and neutron diffraction (ND) measurements show that ACC has a structure partially similar to that of monohydrocalcite, suggesting that ACC is transferred to the crystalline calcium carbonate starting from its crystal nucleus. Rietveld analysis of the ND data showed that the ACC that removed Sr was crystallized to calcite. However, the SrO coordination analyzed using extended X-ray absorption fine structure (EXAFS) implies that the local environment of O around Sr is similar to that in crystalline calcium carbonate aragonite.
Original language | English |
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Pages (from-to) | 225-231 |
Number of pages | 7 |
Journal | Journal of the Ceramic Society of Japan |
Volume | 130 |
Issue number | 2 |
DOIs | |
State | Published - Feb 1 2022 |
Funding
The synchrotron radiation experiments were performed at BL01B1 and BL04B2 of SPring-8 with the approval of the Japan Synchrotron Radiation Reserch Institute (JASRI) (Proposal Nos. 2018B2095, 2019B1562 and 2019B2091). The pulsed neutron scattering measurements were conducted on NOMAD (Proposal Nos. IPTS-22206 and 22235), Sapallation Neutron Source, a DOE Office of Science User Facilities operated by the Oak Ridge National Laboratory. This research was supported by Hosokawa Powder Technology Foundation (Grant number 19505) and Showa Ikeda Memorial Foundation (to Y.S.). This study was partially supported by a Grant-in-Aid for Transformative Research Areas (A) “Hyper-Ordered Structures Science” (Grant No. 20H05881 and 20H05878). The supports of Dr. T. Ina, H. Masai, and Dr. M. M. Everett in experiments are gratefully appreciated. R. L. S. was supported by the Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division. Acknowledgments The synchrotron radiation experiments were performed at BL01B1 and BL04B2 of SPring-8 with the approval of the Japan Synchrotron Radiation Reserch Institute (JASRI) (Proposal Nos. 2018B2095, 2019B1562 and 2019B2091). The pulsed neutron scattering measurements were conducted on NOMAD (Proposal Nos. IPTS-22206 and 22235), Sapallation Neutron Source, a DOE Office of Science User Facilities operated by the Oak Ridge National Laboratory. This research was supported by Hosokawa Powder Technology Foundation (Grant number 19505) and Showa Ikeda Memorial Foundation (to Y.S.). This study was partially supported by a Grant-in-Aid for Transformative Research Areas (A) “Hyper-Ordered Structures Science” (Grant No. 20H05881 and 20H05878). The supports of Dr. T. Ina, H. Masai, and Dr. M. M. Everett in experiments are gratefully appreciated. R. L. S. was supported by the Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division.
Keywords
- Adsorbent
- Amorphous materials
- Calcium carbonate
- Neutron diffraction
- X-ray diffraction