Selenite sorption by carbonate substituted apatite

Abstract

The sorption of selenite, SeO, by carbonate substituted hydroxylapatite was investigated using batch kinetic and equilibrium experiments. The carbonate substituted hydroxylapatite was prepared by a precipitation method and characterized by SEM, XRD, FT-IR, TGA, BET and solubility measurements. The material is poorly crystalline, contains approximately 9.4% carbonate by weight and has a surface area of 210.2 m/g. Uptake of selenite by the carbonated hydroxylapatite was approximately an order of magnitude higher than the uptake by uncarbonated hydroxylapatite reported in the literature. Distribution coefficients, K, determined for the carbonated apatite in this work ranged from approximately 4200 to over 14,000 L/kg. A comparison of the results from kinetic experiments performed in this work and literature kinetic data indicates the carbonated apatite synthesized in this study sorbed selenite 23 times faster than uncarbonated hydroxylapatite based on values normalized to the surface area of each material. The results indicate carbonated apatite is a potential candidate for use as a sorbent for pump-and-treat technologies, soil amendments or for use in permeable reactive barriers for the remediation of selenium contaminated sediments and groundwaters.

Mechanical, pH and Thermal Stability of Mesoporous Hydroxyapatite

“…6 left). It is noteworthy that there are two small vibration bands at 1455 and 1412 cm −1 that correspond to v 3 CO 3 2− adsorbed from the air onto the surface of HAP, diminishing at higher temperatures showing that the carbonate ion is released [31,32].…”

Preparation of ultra-flame retardant wood materials with mechanical reinforcement and water resistance through biomimetic mineralization of carbonated apatite

“…As shown in Fig. 3c, there was typical characteristic peaks of cellulose crystal at 16.0 o and 22.5 o for the natural wood (Peter et al, 2021), CAp showed two characteristic peaks at 25.9 o and 31.6 o , which were attributed to crystal plane (002) and (211), respectively (Moore et al, 2016). For the CAp@wood 75G sample, the two peaks of natural wood were weakened as the crystal structure of cellulose was broken partly and the characteristic peaks at 25.9 o and 31.6 o were appeared.…”

Carbonate Hydroxyapatite - A Multifunctional Bioceramics with Non-Medical Applications

“…In the study of the effect of ammonium carbonate on the formation of calcium-deficient hydroxyapatite, lower levels of carbonation still maintained the sharper peaks and crystalline structure of hydroxyapatite. As the degree of carbonation increased, the peaks became broader, and crystallinity reduced [152,[155][156][157]. Generally, peaks between 20 o and 28 o represent the (002) plane while those between 31 and 50 o represent 211, 213, 222, 300 and 310 planes of apatites (Fig.…”