Institute of Fundamental Technological Research

Due to the growing pollution of the environment, water purification methods have to be improved. One of the most effective solutions is the removal of heavy metal ions by porous materials, including hydroxyapatite. Lao Cai Province in Vietnam has a tremendous reservoir of apatite ore that can be a precursor for nanostructural materials. In this paper, we refer to the recent studies on removing heavy metal salts, including the cobalt and chromium ions, from the wastewater by the nanostructural hydroxyapatite obtained from the apatite ore gained in the Lao Cai Province. The measurements were performed according to the pH, mass of the adsorbent addition into the real wastewater solution, and time exposition onto the adsorbent; and the suitable condition is a dose of modified apatite of 1 g/L; contacting time of 60 minutes and 6 g/L and 15 minutes in the pH range from pH0 (3.76 and 6.57) to neutral pH corresponding to Cr3+ and Co2+. We show that just a small amount of the nanostructural hydroxyapatite can work efficiently to remove the chromium and cobalt ions from the solution with maximum adsorption capacity is 70.37 mg/g and 13.52 mg/g, respectively.

nanostructural hydroxyapatite, apatite ore, wastewater treatment, heavy metal ions removal, novel ecofriendly adsorbent

In this work, we report on the fabrication of nanocomposites based on superparamagnetic iron oxide nanoparticles (SPIONs) in combination with hydroxyapatite (HAp) as a platform for drug delivery and magnetic hyperthermia application. First, the influence of experimental conditions such as co-precipitant, bath temperature, and pH on the morphology and magnetic properties of SPIONs was investigated. Then, the superparamagnetic particles were coated with the hydroxyapatite layer for further loading of anticancer drugs, determining the optimal thickness of the HAp shell. The composite was fabricated by the wet chemical process and was characterized by optimizing the experimental conditions of the wiring synthesis to obtain the superparamagnetic spherical material with a high HAp loading as a platform for drug uptake. SEM and TEM studies confirmed the round shape of the magnetic core up to 15 nm in size with a well-defined HAp shell. After checking the material’s superparamagnetic properties, the temperature dependence on time and alternating magnetic field strength was tested and optimized in hyperthermia experiments.

superparamagnetic iron oxide nanoparticles (SPIONs), hydroxyapatite, nanocomposite, magnetic hyperthermia

In this work, we present magnetic nanoparticles based on iron oxide doped with zinc syn-
thesized using the wet co-precipitation method for environmental application. The morphology of the
samples was revealed by SEM and TEM, which showed particles of granular shape and size of about
15 nm. The specific surface areas of the materials using the BET method were within the range of 85.7 to 101.5 m2 g−1 depending on the zinc content in the superparamagnetic iron oxide nanoparticles (SPI-ONs). Magnetometry was performed to determine the magnetic properties of the particles, indicating superparamagnetism. Synthesized magnetic nanoparticles with different amounts of zinc dopant were used as an adsorbent to remove model pollutant Titan yellow (TY) from the aqueous solutions. Adsorption was determined by investigating the effects of sorbent amount, dye concentration, and contact time. The synthesized material removed Titan yellow quickly and efficiently within the phys-ical adsorption. The adsorption isotherms were consistent with the models proposed by Langmuir and Redlich-Peterson. The monolayer adsorption capacities were 30 and 43 mg g−1 for Fe3O4 and Fe3O4@10%Zn, respectively, for the removal of TY. However, that of Congo red is 59 mg g−1 by Fe3O4@10%Zn. The proposed nanoparticles offer fast and cost-effective water purification, and they can be separated from solution using magnets.

perparamagnetic particles, pollution treatment, Titan yellow, Congo red, adsorption isotherm, iron oxide