Synthesis Of Mg/Al Hydrotalsite-Magnetite As CN- Ion Adsorbent On Wastewater Tapioca Industry

Cyanide compounds contained in tapioca industrial wastewater are relatively high, so it is necessary to reduce cyanide levels. This study utilizes the hydrotalcite-magnetite ability to adsorption of CN- ions. The composite formation process is carried out by mixing the magnetite phase at the stage of hydrotalcite-magnetite synthesis. The characterization of X-Ray Diffraction (XRD) shows reflection of the magnetite peak of 2θ 21.42°; 30,28°; 33.40°;35.65° and 37°. While the peak of hydrotalocites at an angle of 11.66° ; 23,33° ; 34,80° ; 60,92° ; and 62.21°. This result is supported by ir spectra on hydrotalocytes shown by O-H group at wave number 3441 cm-1, O=C-O at wave numbers 1359 cm-1, M-O and M-OH at wave numbers 964 cm-1, 797 cm-1 and 673 cm-1. Fe-O and Fe-OH absorption from magnetites at wave numbers 892 cm-1, 798 cm-1 and 629 cm-1. 0.4 grams of hydrotalcite-magnetite at 30 minutes of stirring absorbed 0.0490 mg/L of cyanide from tapioca liquid waste solution. The value of adsorption capacity is 0.022 mg/g and the adsorption efficiency is 87.96%. The hydrotalcite-magnetite adsorption method is superior to aerob and anaerobic methods using bacteria in the tapioca industry.

Investigation of Thermophysical Properties of Nanomagnetite-based Polymer Materials

In this work, samples of magnetite nanoparticles are synthesized using various synthetic methods. It is shown that of the existing methods of magnetite synthesis, the most widespread is the method of coprecipitation of Fe2+ and Fe3+ salts. Less common, but of interest due to the slower and more controlled kinetics of particle nucleation, is the Fe2+ oxidation method. However, magnetite is unstable and under external influences its phase transition to maghemite can occur, which leads to a change in magnetic characteristics and a change in biological responses. After analyzing the results of the study of samples by the XRD method, the following conclusions can be drawn: The magnetite phase was identified by the characteristic peaks in the diffraction patterns for all samples, except for the sample with EDTA, which may be a consequence of an insufficient amount of the introduced oxidant, or poor diffusion of the oxidant to iron ions due to the formed chelate complex. It can be concluded that magnetite is a promising material for its use in industry and medicine.

Study of Magnetite Nanoparticles by the Method of Mössbauer Spectroscopy

In this work, we studied the Mössbauer spectra of magnetite samples of various compositions. To protect magnetite from oxidation, the resulting particles are coated with protective shells, among which silanes are promising, which polymerize on the surface of magnetite nanoparticles, forming strong covalent bonds. The coating of nanoparticles protects them from aggressive environmental influences, evens out their size distribution, and also protects the environment from the possible toxic effects of the particles themselves. It was shown that the magnetite phase predominates in the sample of native particles, the coating of native particles with alkoxysilane does not lead to fundamental changes in the phase state of the sample particles, and oxidation with nitric acid leads to the complete transformation of magnetite into maghemite. It is obvious that the reason for the distortions of the relaxation nature in the Mössbauer spectra of the samples is the small sizes of the iron-containing domains, which allows us to consider the description of the spectra within the framework of the model of multilevel superparamagnetic relaxation.

Physicochemical properties of chitosan–magnetite nanocomposites obtained with different pH

The physicochemical properties of the nanoparticle surface determine the performance of nanocomposites in biomedical applications such as their biodistribution and pharmacokinetics. The physicochemical properties of chitosan, such as apparent charge density and solubility, are pH dependent. Similarly, Fe3O4 nanoparticles are susceptible to variations in their physicochemical properties due to changes in pH. In this work, we evaluated the physicochemical properties of chitosan–magnetite nanocomposites that were suspended at pH 7.0, 9.0, and 11.0 to determinate the effect on particle size, zeta potential, and mass percentage of the polymeric coating, in addition to the crystalline phase and magnetic properties of magnetite phase. X-ray diffraction results exposed that the present phase was magnetite with no other phases present and that the crystallite size was between 10.8 and 14.1 nm. Fourier transform infrared verified the chitosan functional groups in treated samples while the percentage of mass determined by TGA found to be nearly 9%. Scanning electron microscopy micrographs corroborated the spherical shape of the bare and chitosan-coated nanoparticles. Dynamic light scattering results showed that chitosan coating modifies the zeta potential, going from a potential of −11.8 mV for bare particles to −3.0 mV (pH 11). Besides, vibrating sample magnetometer measurements showed that coercivity remained very low, which is desirable in biomedical applications.

Large exchange bias in Cr substituted Fe3O4 nanoparticles with FeO subdomains

Here we present a structural and magnetic characterization of a novel bimagnetic nanoparticle composed of a 40 nm Cr-substituted magnetite phase with 4 nm FeO subdomains exhibiting large exchange bias.

Photochemical reduction of nanocrystalline maghemite to magnetite

We present a method for the photochemical conversion of the inverse spinel iron oxides in which the mixed-valent magnetite phase (Fe3O4) is accessed from the maghemite phase (γ-Fe2O3) via a stable, colloidal nanocrystal-to-nanocrystal transformation.

Synthesis and Electrochemical Characterisation of Magnetite Coatings on Ti6Al4V-ELI

Titanium alloys have been widely employed in implant materials owing to their biocompatibility. The primary limitation of these materials is their poor performance in applications involving surfaces in mutual contact and under load or relative motion because of their low wear resistance. The aim of this work is to synthesis magnetite coatings on the Ti6Al4V-ELI alloy surface to increase corrosion resistance and to evaluate its electrochemical behaviour. The coatings were obtained using potentiostatic pulse-assisted coprecipitation (PP-CP) on a Ti6Al4V-ELI substrate. The preliminary X-Ray Diffraction (XRD) results indicate the presence of the magnetite coating with 8–10 nm crystal sizes, determined for the (311) plane. Using X-ray photoelectron spectroscopy (XPS), the presence of the magnetite phase on the titanium alloy was observed. Magnetite coating was homogeneous over the full surface and increased the roughness with respect to the substrate. For the corrosion potential behaviour, the Ti6Al4V-ELI showed a modified Ecorr that was less active from the presence of the magnetite coating, and the impedance values were higher than the reference samples without coating. From the polarization curves, the current density of the sample with magnetite was smaller than of bare titanium.

Evaluation of Titania-Rich Slag Produced from Titaniferous Magnetite Under Fluxless Smelting Conditions

Titanium-bearing magnetite ore is generically defined as magnetite with > 1% titanium dioxide (TiO2) and is usually vanadium-bearing. The iron and titanium occur as a mixture of magnetite (Fe3O4) and ilmenite (FeTiO3) with vanadium oxide usually occurring within the solid solution of the titanium-bearing magnetite phase. These ores are currently widely processed in blast furnaces via modified ironmaking processes. Typically, vanadium is recovered as a by-product from the ironmaking process, while the diluted titania slag is stockpiled. Fluxless smelting in a direct-current open-arc furnace is proposed as an opportunity to improve iron and vanadium recovery and potentially unlock the titanium as a slag product. Slags produced from a pilot study are compared to industrial slags produced from ilmenite. The findings from the pilot test show that slag produced under fluxless smelting conditions in an open-arc electric furnace is remarkably similar to industrial ilmenite slags. The test conditions were varied to evaluate the slag and metal composition, and furnace operation, under increasing reducing conditions. The study showed that the slag and metal product was remarkably similar to industrial slag produced from ilmenite.

Preparation and Microwave Absorbing Properties of Natural Ferrites from Corrosion Product as Radar Absorber Materials in X-Band

Rust is the by product of oxidation on ferrous metal. Rust is extremely harmful and can’t be avoided. Due to that reason for added values on rust a research titled utilizing corrosion product as absorber for microwave on X-band frequency is done. This research goals are to determine the ability of rust to absorb radar waves by maximum reflection loss values. The study was conducted by taking a powder natural ferrites of rust from corroded ferrous metal in Surabaya, Malang, Bangkalan and then later separated by using a 0.1 T hard magnet. The XRF, XRD and VSM characterization showed that rust powder sample has chemical compound of ferrites (Fe3O4) with magnetite phase and a soft magnetic with Ms = 8 emu/g. Based on the measurement microwave absorbing by VNA showed that maximum reflection loss of natural ferrites Surabaya, Malang, Bangkalan respectively-20.15 dB, -12.64 dB and-6.75 dB, at matching frequency 11 GHz and width frequency 3 GHz.