Open AccessINFLUENCE OF THE CRYSTAL-CHEMICAL STRUCTURE IN CALCIUM-PHOSPHATE NANOCOMPOSITE ON THE FORMATION OF ELECTROSURFACE AND ACID-BASIC PROPERTIES
Author(s) -
M. Troubitsin,
Viet Hung Hoang,
Л. Фурда
Publication year - 2021
Publication title -
vestnik bgtu im. v.g. šuhova
Language(s) - English
Resource type - Journals
ISSN - 2071-7318
DOI - 10.34031/2071-7318-2021-6-2-89-99
Subject(s) - hydroxyapatites , aqueous solution , zeta potential , inorganic chemistry , phosphate , adsorption , surface charge , calcium carbonate , silicate , precipitation , nanocomposite , chemical engineering , scanning electron microscope , calcium silicate , materials science , carbonate , chemistry , nanoparticle , calcium , organic chemistry , nanotechnology , physics , meteorology , engineering , composite material
The single-phase modified nanostructured hydroxyapatites and biomimetic calcium-phosphate nanocomposite (BMHAP) doped by silicate and carbonate anions are synthesized by chemical precipitation in aqueous solutions. The chemical composition of the obtained samples is studied by energy dispersive X-ray spectroscopy using a scanning electron microscope. It is shown that the obtained molar ratios are close to the design values in all samples. The influence of different modifying ions in the crystal-chemical structure of hydroxyapatite (HAp) on the electrosurface properties of the synthesized products has been studied. Unmodified hydroxyapatite, silicate-substituted hydroxyapatite, and BMHAP particles are found to carry a negative charge in an aqueous suspension at pH = 7, while carbonate-substituted HAp particles had a positive charge. It is revealed that the introduction of silicate and carbonate anions into the HAp structure is accompanied by an increase in negative values of the zeta-potential from -1.05 to -4.29 mV. The change in the distribution of active centers on the surface of modified nanostructured hydroxyapatites is studied by the adsorption of acid-base indicators method with pKax in the range from -0.3 to +12.8. In contrast to stoichiometric hydroxyapatite, in BMHAP the neutral Bronsted centers prevails, and their concentration is 48.38 mmol-eq/g