title: Synthesis, Structural, and Adsorption Properties and Thermal Stability of Nanohydroxyapatite/Polysaccharide Composites.
abstract: A series of composites based on nanohydroxyapatite (nHAp) and natural polysaccharides (PS) (nHAp/agar, nHAp/chitosan, nHAp/pectin FB300, nHAp/pectin APA103, nHAp/sodium alginate) was synthesized by liquid-phase two-step method and characterized using nitrogen adsorption-desorption, DSC, TG, FTIR spectroscopy, and SEM. The analysis of nitrogen adsorption-desorption data shows that composites with a nHAp: PS ratio of 4:1 exhibit a sufficiently high specific surface area from 49 to 82 m2/g. The incremental pore size distributions indicate mainly mesoporosity. The composites with the component ratio 1:1 preferably form a film-like structure, and the value of SBETvaries from 0.3 to 43 m2/g depending on the nature of a polysaccharide. Adsorption of Sr(II) on the composites from the aqueous solutions has been studied. The thermal properties of polysaccharides alone and in nHAp/PS show the influence of nHAp, since there is a shift of characteristic DSC and DTG peaks. FTIR spectroscopy data confirm the presence of functional groups typical for nHAp as well as polysaccharides in composites. Structure and morphological characteristics of the composites are strongly dependent on the ratio of components, since nHAp/PS at 4:1 have relatively large SBETvalues and a good ability to adsorb metal ions. The comparison of the adsorption capacity with respect to Sr(II) of nHAp, polysaccharides, and composites shows that it of the latter is higher than that of nHAp (per 1 m2of surface).
authors.affiliation: Department of Radiochemistry and Colloids Chemistry, Faculty of Chemistry, Maria Curie-Sklodowska University, M. Curie-Sklodowska Sq. 3, 20-031, Lublin, Poland.
authors.forename: Ewa
authors.initials: E
authors.lastname: Skwarek
authors.affiliation: Chuiko Institute of Surface Chemistry, National Academy of Science of Ukraine, 17 General Naumov Street, 03164, Kiev, Ukraine. iscgoncharuk@meta.ua.
authors.forename: Olena
authors.identifier: http://orcid.org/0000-0002-2554-8297
authors.initials: O
authors.lastname: Goncharuk
authors.affiliation: Department of Physicochemistry of Solid Surface, Faculty of Chemistry, Maria Curie-Sklodowska University, M. Curie-Sklodowska Sq. 3, 20-031, Lublin, Poland.
authors.forename: Dariusz
authors.initials: D
authors.lastname: Sternik
authors.affiliation: Department of Radiochemistry and Colloids Chemistry, Faculty of Chemistry, Maria Curie-Sklodowska University, M. Curie-Sklodowska Sq. 3, 20-031, Lublin, Poland.
authors.forename: Wladyslaw
authors.initials: W
authors.lastname: Janusz
authors.affiliation: Department of Theoretical Chemistry, Faculty of Chemistry, Maria Curie-Sklodowska University, M. Curie-Sklodowska Sq. 3, 20-031, Lublin, Poland.
authors.forename: Karolina
authors.initials: K
authors.lastname: Gdula
authors.affiliation: Chuiko Institute of Surface Chemistry, National Academy of Science of Ukraine, 17 General Naumov Street, 03164, Kiev, Ukraine.
authors.forename: Vladimir M
authors.initials: VM
authors.lastname: Gun'ko
keywords: Agar; Chitosan; Composites; High- and low-esterified pectins; Nanohydroxyapatite; Sodium alginate; Sr(II) adsorption