This paper reports the synthesis of Fe3O4 nanoparticles with a hydrophobic surface functionalized with oleic acid through a simple and efficient route in air atmosphere and by co-precipitation. The hydrophobic surfactant agent was added in the magnetic crystal growth stage. Magnetic nanofluid was obtained by ultrasonic dispersion of magnetic nanoparticles in a carrier liquid � vegetable oil. The sample as powder has been characterized by X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy, Transmission Electron Microscopy (TEM), and Vibrating Sample Magnetometry (VSM) at room temperature. The magnetic nanofluid in vegetal oil was investigated by determining the stability of the nanoparticles in the vegetable oil through UV-Vis spectrometry method, the magnetic properties through Vibrating Sample Magnetometry (VSM) method at room temperature, and thermal conductivity as function of magnetic nanoparticles volume concentration and of temperature.

The hydrophilic g-Fe2O3 nanoparticles coated with polyvinylpyrrolidone (PVP) were prepared in one step of the modified polyol method combined with an additional heat treating. The presence of maghemite (g-Fe2O3) phase was confirmed by using X-ray diffraction (XRD) and Raman Spectrometry on powder. FT-IR spectroscopy confirmed the presence of PVP on the nanoparticles surface and the Zeta potential also supported the coating of nanoparticles with a layer of PVP and a good stability in aqueous medium. SEM analysis showed that the prepared g-Fe2O3 nanoparticles have a spherical structural morphology with the tendency of agglomeration. Hysteresis loop shows a ferromagnetic behaviour at room temperature with a saturation magnetization up to 57 emu/g.

This paper reports the synthesis of FeNi3 alloy nanoparticles by chemical reduction of the Fe2+ and Ni2+ ions, from the corresponding chlorides, with hydrazine (N2H4�H2O) as a reducing agent in aqueous solution at room temperature by modifying the molar ratio of the ions Fe2+: Ni2+, reaction time, with and without amine-type growth promoter, and reducing both, with or without ultrasonic aid. The FeNi3 alloy nanoparticles have been investigated by XRD, EDS spectrum analysis, SEM and VSM. When the molar ratio of Fe2+ and Ni2+ is equal to 1:3, reducing both, with or without ultrasonic aid, Fe2+ and Ni2+ were completely reduced into Fe and Ni, resulting FeNi3 alloy with a face-centered cubic (fcc) crystal structure. EDS analysis supported the presence of metal ions in atomic weight corresponding to the stoichiometric ratio of initial reaction. SEM analysis showed that nanoparticles of FeNi3 alloy have a spherical structural morphology. Hysteresis loop show a ferromagnetic behaviour of the FeNi3 alloy nanoparticles at room temperature.

The removal of toxic heavy metal ions such as lead and zinc from industrial and mining wastewaters has been widely studied because their existence in surface and underground water is responsible for several types of health problems caused to animals and human beings. Also, there are some organic compounds, which must be prevented from reaching in drinking water from various sources of pollution. For these reasons in this paper the experiments were conducted to study the ability of activated carbon for removal of Pb(II), Zn(II), C6H6, C6H5-CH3 from water. In addition to the data from the literature showing the actived carbon efficiency for removing of the organic nature pollutants from water, in this article the study is done also on inorganic toxic pollutants (lead and zinc heavy metals) that can exist in water. The removal efficiency of the tested activated carbon used as adsorbent towards the tested pollutants decreased in the following order: COD (benzene, toluene) > Pb(II) > Zn(II).

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In this study, L-lysine coated �a-Fe2O3 nanoparticles were synthesized by a chemical approach in two steps. In the first step �a-Fe2O3 nanoparticles were synthesized by a polyol-reduction method. XRD analysis confirmed the presence of cubic maghemite phase with an average crystallite size of 9.2 nm. SEM analysis showed that the prepared �a-Fe2O3 nanoparticles have a spherical structural morphology with the tendency of agglomeration and with size in the range 8.36- 10.69 nm. The �a-Fe2O3 nanoparticles were coated with L-lysine in the second stage in an aqueous dispersion with ultrasonication followed by a gentle heating at 40��C. FT-IR spectroscopy confirmed the presence of L-lysine on the nanoparticles surface and the Zeta potential also supported the coating of nanoparticles with a hydrophilic layer of amino acid (L-lysine) and a good stability in aqueous medium. Hysteresis loop shows a ferromagnetic behavior at room temperature for both samples.

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