Surface and Physicochemical Characterization of Phosphates Vivianite, Fe<sub>2</sub>(PO<sub>4</sub>)<sub>3</sub> and Hydroxyapatite, Ca<sub>5</sub>(PO<sub>4</sub>)<sub>3</sub>OH

Abstract

Hydroxyapatite is a calcium phosphate in the apatite group. It has numerous applications due to its particular properties including the sorption of metallic ions. This makes it useful for the treatment of contaminated groundwater and for soil decontamination. The least expensive source of hydroxyapatite for synthesis is bovine bone, since this is a waste material. Vivianite is an iron phosphate which has received little study. Like hydroxyapatite, it has particular properties. This paper describes the method of obtaining these phosphates; calcium phosphate from bovine bone, and iron phosphate by synthesis. Also described are the methods of purifying the materials and characterization of these two phosphates by X-ray diffraction, infrared analysis, thermogravimetric and differential scanning calorimetric analysis, scanning electron microscopy, and surface area by the BET method. Physicochemical characteristics of hydroxyapatite obtained from bovine bone are described, and preliminary results are presented of an investigation into whether hydroxyapatite and iron phosphate are suitable as a permeable reactive barrier for the treatment of metallic and radionuclide contaminants.

Electronic Band Structure and Optical Properties of HgPS3 Crystal and Layers

“…While the 450 cm –1 band is attributed to P–P vibrations, the intense peak located at 597 cm –1 is consistent with every MPS 3 sample assigned to the P–S stretching vibrations . Finally, the broad peak at 1069 cm –1 corresponds to the phosphate bands due to partial oxidation of the surface of the material . Raman spectroscopy was performed in bulk (10–300 K) and exfoliated samples (300 K) without significant differences between them and the results are presented in Figures S7 and S8.…”

Cu(II) and Cd(II) Removal Efficiency of Microbially Redox-Activated Magnetite Nanoparticles

“…The reduction of magnetite by G. sulfurreducens presumably caused partial dissolution of some Fe 2+ which precipitated as vivianite in the PO 4 3– -rich medium used in this study. , Based on the relatively low intensity of the reflections in the XRD patterns, coupled to previous measurements of the SSA of vivianite of 8–16 m 2 /g, , we anticipate that the effect of vivianite in this system was minor and did not influence the adsorption experiments. The Scherrer equation (eq ) was used to calculate the average crystal size , of 9.59 nm for mag red and 10.23 nm for mag ox and 10.29 nm for mag nat .…”

A review of near infrared spectroscopic features of teeth, bone and artificial hydroxyapatite

“…38 Wavenumbers between 1459 and 1413 cm −1 are attributed to asymmetric stretching (v 3 ). 39 Some vibrational modes in carbonates feature overlapping peaks, including ν 3 (near 1450 cm −1 ), and combined modes ν 1 + ν 4 (near 1800 cm −1 ), and ν 1 + ν 3 (near 2500 cm −1 ). 38…”

“…38 The MIR absorption spectrum of HAp is characterised by large features associated with phosphate in the range 1000–1150 cm −1 , with peaks at 1094 and 1045 cm −1 due to v 3 asymmetric stretching, and OH bands at 3572 (stretching) and 634 cm −1 (vibration). 39 The (PO 4 ) 3− symmetric stretching mode (ν 1 ) is reported to be at 938 cm −1 . 40 Free phosphate oxyanions in aqueous solutions were reported to display the symmetric bending mode (ν 2 ) at 420 cm −1 , the asymmetric stretching mode (ν 3 ) at 1017 cm −1 and the ν 4 mode at 567 cm −1 .…”