Modification of hydroxyapatite with ion-selective complexants [electronic resource] : 1-hydroxyethane-1,1-diphosphonic acid
- Washington, D.C. : United States. Dept. of Energy. Office of Basic Energy Sciences, 2014.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy
- Physical Description:
- pages 585-596 : digital, PDF file
- Additional Creators:
- United States. Department of Energy. Office of Basic Energy Sciences
United States. Department of Energy. Office of Scientific and Technical Information
- Hydroxyapatite (HAP) was modified with 1-hydroxyethane-1,1-diphosphonic acid (HEDP), and its effect on divalent metal ion binding was determined. HAP was synthesized from calcium hydroxide and phosphoric acid. After calcination, it was modified with HEDP, and the influence of time and temperature on the modification was investigated. HEDP incorporation increased as its initial solution concentration increased from 0.01 to 0.50 M. Unmodified and modified HAP were characterized using Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, and specific surface area analysis. Ca/P ratios, acid capacities, and phosphorus elemental analyses gave the effect of modification on composition and surface characteristics. A high reaction temperature produced new phosphonate bands at 993, 1082, and 1144 cm<sup>–1</sup> that indicated the presence of HEDP. HAP modification at a high temperature–long reaction time had the highest HEDP loading and gave the sharpest XRD peaks. The emergence of new HAP–HEDP strands was observed in SEM images for treated samples while EDS showed high phosphorus contents in these strands. Modified HAP had a high acid capacity from the additional P–OH groups in HEDP. The P(O)OH groups maintain their ability to bind metal ions within the HAP matrix: contacting the modified HAP with 10–4 N nitrate solutions of five transition metal ions gives an affinity sequence of Pb(II) > Cd(II) > Zn(II) > Ni(II) > Cu(II). Here, this result is comparable to that of commercially available di(2-ethylhexyl)phosphoric acid, a common solvent extractant, and the trend is consistent with the Misono softness parameter of metal ion polarizabilities.
- Published through SciTech Connect.
Industrial and Engineering Chemistry Research 54 2 ISSN 0888-5885 AM
Yasmine Daniels; Nathalie Lyczko; Ange Nzihou; Spiro D. Alexandratos.
Hunter College, New York, NY (United States)
- Funding Information:
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