Superparamagnetic Nanocomposite of Magnetite-Chitosan Using Oleic Acid as Anti Agglomeration and Glutaraldehyde as Crosslinkage Agent

In this research magnetite was synthesized by coprecipitation method, in which solution of NH4OH was added into the solution containing a mixture of Fe2+/Fe3+ (molar ratio 1:2) until pH 11 under strong ultrasonic agitation for 30 min. The black sediment of magnetite was filtered, washed and dried. The product was then modified by using oleic acid to prevent agglomeration. Chitosan was prepared by deacetilization of chitin, whereas chitin was extracted from shrimp shell. In the synthesis of nanocomposite, 0.5 g of chitosan and 1.5 g of oleic acid modified magnetite were introduced into 100 mL of 2% acetic acid solution, followed by sonication treatment for 10 min and magnetic stirring for 20 min. In order to perform the cross-linkage reaction, solution of 2% glutaraldehyde was added into the mixture at temperature of 40 °C for 3 h. The composite was collected by magnetic separation, followed by washing with distilled water and ethanol in a row. The product was dried and characterized by XRD, FTIR, TEM and VSM methods. The result showed that the composite had good crystal structure with a cubic inverse spinel structure, monodisperse and quasi sphere in shape with diameter of 20–25 nm. It had high saturation magnetization (43.4 emu/g) and superparamagnetic property.

NaCl-induced nickel–cobalt inverse spinel structure for boosting hydrogen evolution from ethyl acetate and water

Novel NaCl-induced nickel–cobalt inverse spinel nanoclusters are designed for boosting H2 evolution from ethyl acetate and water.

The Effect of the Fe2+B/Fe3+B Ratio on Electric Conductivity and Corrosion Resistance of Anodes

The effect of the Fe2+B/Fe3+B ratio (the ratio of divalent and trivalent iron ion in B position of the inverse spinel structure) in cermets on the electric conductivity and corrosion resistance of anodes was investigated. The experimental results showed that both the electrical conductivity and corrosion resistance are proportional to the Fe2+B/Fe3+B ratio on the surface of anodes because FeAl2O4 and NiAl2O4 are produced on the surface of the anode and Fe3+ in the NiFe2O4 is corroded preferentially during electrolysis.

Catalytic reduction of NOx by CO over a Ni–Ga based oxide catalyst

A new low-cost Ni–Ga based oxide catalyst with an inverse spinel structure was developed for NO removal. Our results open up a new route for designing efficient catalysts, combining the strong gas capture properties of a specific element with high catalytic NO conversion properties, by constructing an appropriate element ligand environment.

Synthesis of Magnetic Particles and Silica Coated Core-Shell Materials

Ferrite particles were prepared by hydrothermal process at high temperature. The characterization of ferrite was examined by XRD, Mössbauer spectrum, and SEM. The XRD and Mössbauer spectrum confirmed that ferrite particles have a Fe3O4 inverse spinel structure, the SEM results show that each Fe3O4 particles were composed of many smaller magnetite nanoparticles. The as-synthesized Fe3O4 particles were modified by sodium citrate then further coated with SiO2 layer through the modified stöber method. The composited Fe3O4@SiO2 microspheres exhibited outstanding monodispersity and magnetic property.

Study of the Inorganic Ion Exchanger Li3Mn0.25Ti0.5O3

Inorganic ion exchanger (Li3Mn0.25Ti0.5O3) with an inverse spinel structure was synthesized by solid state reaction crystallization method. The results showed that the Li+ extraction/insertion be progressed mainly by an ion-exchange mechanism. The acid treated samples had an ion exchange capacity of 9.2mmol/g for Li+.