X-Ray absorption spectroscopy studies on the structure of a biogenic “amorphous” calcium carbonate phase †

2000 ◽  
pp. 3977-3982 ◽  
Author(s):  
Yael Levi-Kalisman ◽  
Sefi Raz ◽  
Steve Weiner ◽  
Lia Addadi ◽  
Irit Sagi
Keyword(s):  
Calcium Carbonate ◽  
Absorption Spectroscopy ◽  
Amorphous Calcium Carbonate ◽  
Carbonate Phase ◽  
X Ray ◽  
Spectroscopy Studies ◽  
X Ray Absorption

scholarly journals The Crystallization Process of Vaterite Microdisc Mesocrystals via Proto-Vaterite Amorphous Calcium Carbonate Characterized by Cryo-X-ray Absorption Spectroscopy

Crystals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 750
Author(s):  
Li Qiao ◽  
Ivo Zizak ◽  
Paul Zaslansky ◽  
Yurong Ma
Keyword(s):  
Calcium Carbonate ◽  
Absorption Spectroscopy ◽  
Formation Mechanism ◽  
Crystallization Process ◽  
Crystallization Time ◽  
Ordered Structure ◽  
Amorphous Calcium Carbonate ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption

Investigation on the formation mechanism of crystals via amorphous precursors has attracted a lot of interests in the last years. The formation mechanism of thermodynamically meta-stable vaterite in pure alcohols in the absence of any additive is less known. Herein, the crystallization process of vaterite microdisc mesocrystals via proto-vaterite amorphous calcium carbonate (ACC) in isopropanol was tracked by using Ca K-edge X-ray absorption spectroscopy (XAS) characterization under cryo-condition. Ca K-edge X-ray absorption near edge structure (XANES) spectra show that the absorption edges of the Ca ions of the vaterite samples with different crystallization times shift to lower photoelectron energy while increasing the crystallization times from 0.5 to 20 d, indicating the increase of crystallinity degree of calcium carbonate. Ca K-edge extended X-ray absorption fine structure (EXAFS) spectra exhibit that the coordination number of the nearest neighbor atom O around Ca increases slowly with the increase of crystallization time and tends to be stable as 4.3 (±1.4). Crystallization time dependent XANES and EXAFS analyses indicate that short-range ordered structure in proto-vaterite ACC gradually transform to long-range ordered structure in vaterite microdisc mesocrystals via a non-classical crystallization mechanism.

scholarly journals In Situ X-ray Absorption Spectroscopy Studies of Discharge Reactions in a Thick Cathode of a Lithium Sulfur Battery

2016 ◽  
Vol 164 (2) ◽  
pp. A18-A27 ◽  
Author(s):  
Kevin H. Wujcik ◽  
Dunyang Rita Wang ◽  
Tod A. Pascal ◽  
David Prendergast ◽  
Nitash P. Balsara
Keyword(s):  
Absorption Spectroscopy ◽  
X Ray ◽  
Lithium Sulfur Battery ◽  
Spectroscopy Studies ◽  
Sulfur Battery ◽  
X Ray Absorption ◽  
Lithium Sulfur

scholarly journals Effects of ZnO nanoparticles in alfalfa, tomato, and cucumber at the germination stage: Root development and X-ray absorption spectroscopy studies

2013 ◽  
Vol 85 (12) ◽  
pp. 2161-2174 ◽  
Author(s):  
Guadalupe de la Rosa ◽  
Martha Laura López-Moreno ◽  
David de Haro ◽  
Cristian E. Botez ◽  
José R. Peralta-Videa ◽  
...  
Keyword(s):  
Seed Germination ◽  
Absorption Spectroscopy ◽  
Root Elongation ◽  
Dry Weight ◽  
Zno Nps ◽  
X Ray ◽  
Zn Content ◽  
Spectroscopy Studies ◽  
X Ray Absorption ◽  
Germination Stage

Past reports indicate that some nanoparticles (NPs) affect seed germination; however, the biotransformation of metal NPs is still not well understood. This study investigated the toxicity on seed germination/root elongation and the uptake of ZnO NPs and Zn2+ in alfalfa (Medicago sativa), cucumber (Cucumis sativus), and tomato (Solanum lycopersicum) seedlings. Seeds were treated with ZnO NPs at 0–1600 mg L–1 as well as 0–250 mg L–1 Zn2+ for comparison purposes. Results showed that at 1600 mg L–1 ZnO NPs, germination in cucumber increased by 10 %, and alfalfa and tomato germination were reduced by 40 and 20 %, respectively. At 250 mg Zn2+ L–1, only tomato germination was reduced with respect to controls. The highest Zn content was of 4700 and 3500 mg kg–1 dry weight (DW), for alfalfa seedlings germinated in 1600 mg L–1 ZnO NPs and 250 mg L–1 Zn2+, respectively. Bulk X-ray absorption spectroscopy (XAS) results indicated that ZnO NPs were probably biotransformed by plants. The edge energy positions of NP-treated samples were at the same position as Zn(NO3)2, which indicated that Zn in all plant species was as Zn(II).

In Situ X-Ray Absorption Spectroscopy Studies of Carbon Monoxide Oxidation in the Presence of Nanocomposite Cu–Fe–Al Oxide Catalysts

2021 ◽  
Vol 62 (1) ◽  
pp. 160-171
Author(s):  
A. M. Kremneva ◽  
A. V. Fedorov ◽  
A. A. Saraev ◽  
O. A. Bulavchenko ◽  
V. A. Yakovlev ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Absorption Spectroscopy ◽  
Carbon Monoxide Oxidation ◽  
Oxide Catalysts ◽  
X Ray ◽  
Spectroscopy Studies ◽  
X Ray Absorption ◽  
Al Oxide
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