X-ray Photoelectron Spectroscopy Study of Mg Adsorption on Nanocrystalline Hydroxyapatite

• Published in: Inorganic materials Vol. 56; no. 10; pp. 1011 - 1019
• Main Authors: Teterin, Yu. A., Rudin, V. N., Severin, A. V., Paul’, M. E., Maslakov, K. I., Teterin, A. Yu, Dvoryak, S. V.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.10.2020; Springer Nature B.V
• Subjects: Adsorption; Calcium ions; Cations; Chemistry; Chemistry and Materials Science; Hydroxyapatite; Industrial Chemistry/Chemical Engineering; Inorganic Chemistry; Isotherms; Magnesium chloride; Materials Science; Nanocrystals; Oxidation; Photoelectrons; Solid phases; Sorbents; Spectrum analysis; Surface chemistry; Surface layers; Thickness; Valence; X ray photoelectron spectroscopy; hydroxyapatite; adsorption; X-ray photoelectron spectroscopy
• ISSN: 0020-1685; 1608-3172
• DOI: 10.1134/S0020168520100155

— We have studied Mg 2+ adsorption on hydroxyapatite (HAp) nanocrystals and constructed its isotherm at equilibrium cation concentrations in the range 0–0.35 mol/L. For a number of samples, corresponding to characteristic points in the adsorption isotherm, the composition and the oxidation state of the elements present on the surface of the sorbent have been determined by X-ray photoelectron spectroscopy (XPS). The surface magnesium concentration determined by XPS, which detects only ions in a surface layer a few nanometers in thickness, has been found to be considerably lower than the total amount of cations in the solid phase, evaluated from the experimentally determined adsorption isotherm. We assume that, during the sorption process, some of the magnesium ions substitute for calcium ions in the bulk of the HAp and some adsorb in the form of MgCl 2 . The results obtained in this study constitute a fundamental basis for practical solutions in designing integrated medications based on HAp with magnesium.