Paramagnetic Iron-Doped Hydroxyapatite Nanoparticles with Improved Metal Sorption Properties. A Bioorganic Substrates-Mediated Synthesis

Abstract

This paper describes the synthesis of paramegnetic iron-containing hydroxyapatite nanoparticles and their increased Cu 2+ sorbent capacity when using Ca 2+ complexes of soluble bio-organic substrates from urban wastes as synthesis precursors. A thorough characterization of the particles by TEM, XRD, FTIR spectroscopy, specific surface area, TGA, XPS, and DLS, indicates that loss of crystallinity, a higher specific area, an increased surface oxygen content, and formation of surface iron phases strongly enhance Cu 2+ adsorption capacity of hydroxyapatite-based materials. However, the major effect of the surface and morphologycal modifications is the size diminution of the aggregates formed in aqueous solutions leading to an increased effective surface available for Cu 2+ adsorption. Maximum sorption values of 550 -850 mg Cu 2+ per gram of particles suspended in an aqueous solution at pH 7 were determined; almost 10 times the maximum values observed for hydroxyapatite nanoparticles suspensions under the same conditions.

In‐vitro biocompatibility, bioactivity and photoluminescence properties of Eu3+/Sr2+ dual‐doped nano‐hydroxyapatite for biomedical applications

“…The many fold increase in the values indicate chances of kinetic coagulation and the particle agglomerates present within. The particle sizes obtained from XRD and TEM are comparable, but the DLS method give the sizes of agglomerated particles …”

Effect of Humic Substances and Bioorganic Substrates from Urban Wastes in Nanostructured Materials Applications and Synthesis

“…Maximum sorption values of 550-850 mg Cu 2+ per gram of particles suspended in an aqueous solution at pH 7 were obtained, almost 10 times the maximum values observed for pure hydroxyapatite nanoparticles suspensions under the same conditions [18]. Such improvement is correlated with a negatively-charged surface, the presence of phosphate and Fe-OH surface groups.…”

“…Moreover, the organic template stabilizes the microscopic structure of the material upon heat-drying; thus providing a potential solution to the problem of structural changes inherent to sol-gel materials long after the completion of their synthesis. In particular, organic-inorganic hybrid materials involving natural materials offer remarkable hydrodynamic, aerodynamic, wetting, and adhesive properties [18].…”

“…However, a second important effect appears to be the agglomerates size, as agglomeration seems to severely reduce the effective surface available for adsorption in aqueous suspensions. Undoubtly, these materials are a potential, self-sustaining, environmentally friendly, and efficient material for Cu 2+ removal and aqueous effluent remediation [18]. …”

Increased UV absorption properties of natural hydroxyapatite‐based sunscreen through laser ablation modification in liquid

“…This can be explained considering some agglomeration of the particles; indeed such agglomeration and the difference between SEM and DLS results was previously observed for HAp‐based nanomaterial. The agglomeration can be due to the OH groups present in the HAp molecule and the hydrogen bond‐type interactions; the presence of iron ion in the powders also seem to favor the agglomeration …”