Magnetically recoverable iron oxide–hydroxyapatite nanocomposites for lead removal

Abstract

Magnetite-hydroxyapatite nanocomposites were prepared by in situ precipitation of the calcium phosphate phase in an iron oxide colloidal suspension. Homogeneous magnetic powders were obtained with iron oxide content up to 50 wt%, without perturbation of the magnetite structure nor formation of additional calcium phosphates. The surface area of the composite powder was significantly increased after incorporation of magnetite due to the better apatite particle dispersion. This results in an increased available reactive surface, favoring lead sorption and hydroxypyromorphite precipitation, both leading to an enhanced lead removal capacity of the composite materials. The magnetic properties of magnetite nanocrystals were preserved upon association with hydroxyapatite. Full recovery of the composite powder after lead removal could be achieved using a simple magnet at a relatively low iron oxide content (20 wt%). This indicates a strong interaction between hydroxyapatite and magnetite particles within the composite powder. The procedure is simple, easily scalable and involves only environmental friendly materials.

Low-cost composites based on porous titania–apatite surfaces for the removal of patent blue V from water: Effect of chemical structure of dye

“…A significant increase in oxide content is obtained when the sample is previously heated. This result can be explained on the basis of the dehydroxylation of titania, followed by its conversion to the TiO 2 -anatase with a negative charge at its surface [23]. Consequently, the precipitation of TiO 2 with HAp provides a better special repartition of the hydroxyapatite particles resulting thus in novel porous structure involving HAp-oxide interparticle voids [23].…”

“…This result can be explained on the basis of the dehydroxylation of titania, followed by its conversion to the TiO 2 -anatase with a negative charge at its surface [23]. Consequently, the precipitation of TiO 2 with HAp provides a better special repartition of the hydroxyapatite particles resulting thus in novel porous structure involving HAp-oxide interparticle voids [23]. Upon heating, the systematic decrease in specific surface area and the increase in pore size indicate the growth of both particles HAp and titania particles.…”

Zinc oxide-hydroxyapatite nanocomposite photocatalysts for the degradation of ciprofloxacin and ofloxacin antibiotics

“…Among sorbing phases that may be advantageously associated with ZnO, hydroxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 ) appears particularly interesting due to its high capacity for metal ions retention and good sorption properties towards certain organic pollutants, including antibiotics [21][22][23][24][25][26]. The 4 co-precipitation of hydroxyapatite-based nanocomposites with other inorganic phases, such as ZrO 2 , Fe 3 O 4 or TiO 2 , for remediation purpose has already been described [27][28][29]. In particular, Ti-doped hydroxyapatites have shown very promising properties as photocatalysts [30][31][32][33].…”

Isolation of naproxen from wastewater using carbon-based magnetic adsorbents

“…Do et al (2011) produced activated carbon/Fe 3 O 4 nanocomposite for methyl orange adsorption. Yang et al (2014) prepared iron oxidehydroxyapatite nanocomposites for lead adsorption. Magnetic nanoparticles have large specific surface area and small diffusion resistance (Shariati et al 2011).…”