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Rare-earth doped calcium nano ferrites (CaFe2−x−yGdxSmyO4; x = y = 0.0; x = 0.025, y = 0.05) are synthesized by citrate nitrate auto combustion method. The prepared samples are characterized using X-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FTIR), high-resolution transmission electron microscope (HRTEM), and vibrating sample magnetometer (VSM) analyses. After that, the samples were examined for Pb (II) ions removal from the water solution. The orthorhombic structure with space group Pnma is ratified from XRD. The average crystallite size of the synthesized powders is estimated from the broadening of the XRD lines in the range of 18–21 nm. FTIR confirms the molecular signature of the samples. The magnetic property is discussed based on super exchange interactions. The hysteresis loop shows two different magnetic behaviors of the investigated sample as well as increasing the coercivity from 14 to 240 G due to the doping. The electrical parameters are discussed in the basic hopping charge model, while the conduction mechanism of the samples will be discussed based on de-Boer and Verwey. The experimental results are subjected to kinetic and isotherm analyses. The Langmuir and Freundlich isotherms describe the adsorption of heavy metal ions as designated by the high correlation coefficient (R2). The use only 4 mg of the doped sample with low price ferrite nanoparticles has been utilized for 99.31% removal of Pb (II) from wastewater at a contact time of 10 min at room temperature. [ABSTRACT FROM AUTHOR]

The relationship between local structure and visible-light activated photocatalytic effect of simulated domestic waste slag glass–ceramics (R-NaWSFe) was investigated. The largest pseudo-first-order rate constant of 9.75 × 10−3 min−1 was estimated for methylene blue decomposition test under the visible-light irradiation using R-NaWSFe with additional 30 mass% of Fe2O3 heat-treated at 900 °C for 100 min. The reason for the high photoactivity of this sample was mainly due to nanoparticles of CaFe2O4 and α-Fe2O3 confirmed by the Mössbauer spectrum measured at 77 K. It is concluded that the nanoparticles of magnetic components in silica are essential for exhibiting visible-light activated catalytic effect. [ABSTRACT FROM AUTHOR]

Calcium ferrite oxides were prepared by calcining a mixture powder of iron- and calcium oxide. The 57Fe-Mössbauer spectra of the calcium ferrites oxides were measured, revealing that the products should be Ca2Fe2O5 and CaFe2O4, the ratio of which was dependent of the Fe/Ca atomic ratio of the mixture powder. [ABSTRACT FROM AUTHOR]