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The design and synthesis of efficient adsorbents for the recovery of precious metals from secondary resources are of great environmental and economic significance. Herein, a magnetic sulfur‐doped composite CoFe2O4@S–CoWO4 (CF@S–CoWO4) is developed through a hydrothermal synthesis method, which is used to selectively recover gold in aqueous media. Significantly, CF@S–CoWO4 exhibits the best overall performance with gold ions adsorption capacity (Qmax) and distribution coefficient (Kd) are 1049 mg g−1 and 4.4 × 106 mL g−1, respectively, which are much higher than those of other gold adsorption materials. The selectivity coefficients (K) toward other metal ions (Pd2+, Ca2+, Mg2+, Cd2+, Al3+, Li+, Ni+) are also higher, which suggests that CF@S–CoWO4 had a preferential selectivity for Au3+ in coexisting ion solutions. Moreover, the antianion interference of the composite follows the order: SO42− > PO43− > NO3− > CO32−, and it also shows very good reusability with adsorption efficiency at 81.78% after four repeated cycles. Based on characterizations and calculation, it is found that Au(III) mainly undergoes chelation and reduction reactions in the S sites in CF@S–CoWO4, which indicates the important role of S sites. Hence the CF@S–CoWO4 composite demonstrates a promising application for the recycling of gold ions from electronic wastewater. [ABSTRACT FROM AUTHOR]

The design and synthesis of efficient adsorbents for the recovery of precious metals from secondary resources are of great environmental and economic significance. Herein, a magnetic sulfur‐doped composite CoFe2O4@S–CoWO4 (CF@S–CoWO4) is developed through a hydrothermal synthesis method, which is used to selectively recover gold in aqueous media. Significantly, CF@S–CoWO4 exhibits the best overall performance with gold ions adsorption capacity (Qmax) and distribution coefficient (Kd) are 1049 mg g−1 and 4.4 × 106 mL g−1, respectively, which are much higher than those of other gold adsorption materials. The selectivity coefficients (K) toward other metal ions (Pd2+, Ca2+, Mg2+, Cd2+, Al3+, Li+, Ni+) are also higher, which suggests that CF@S–CoWO4 had a preferential selectivity for Au3+ in coexisting ion solutions. Moreover, the antianion interference of the composite follows the order: SO42− > PO43− > NO3− > CO32−, and it also shows very good reusability with adsorption efficiency at 81.78% after four repeated cycles. Based on characterizations and calculation, it is found that Au(III) mainly undergoes chelation and reduction reactions in the S sites in CF@S–CoWO4, which indicates the important role of S sites. Hence the CF@S–CoWO4 composite demonstrates a promising application for the recycling of gold ions from electronic wastewater.

In this article, the authors have explored the changes caused in structural, morphological and magnetic properties of magnesium ferrite nanoparticles (MgFe2O4 NPs) under dynamic shock wave exposure situations. Interestingly, the observed XRD and VSM results reveal that the MgFe2O4 NPs have outstanding crystallographic and magnetic phase stability against the impact of shock waves and found that the title NPs are having higher shock resistance than other potential materials such as TiO2, Co3O4 and ZnFe2O4 NPs.

Nickel oxide nanoparticles with the size of 218, 73, and 50 nm were added to Ni-P electroless coating to create NiO@Ni-P nanoparticle reinforced composite coating on a brass substrate. The nanoparticles were synthesized by the green synthesis method, using Artemisia dracunculus extract. The coatings had amorphous structure and nodular morphology. The results of Tafel and EIS tests showed that the coating containing nickel oxide nanoparticles with an average size of 73 nm, had the highest corrosion resistance. The results of the tribocorrosion test under open circuit potential condition revealed Ni-P-(73 nm)NiO coating had the highest tribocorrosion resistance. Heat treatment at 400°C caused considerable improvement in the saturation and remnant magnetization of the composite coating, the value of saturation and remnant magnetization increased from 5 and 0.1 emu/g for simple Ni-P coating to 12 and 2 emu/g for NiO@Ni-P coating respectively, and the coercive field of the samples also enhanced. [ABSTRACT FROM AUTHOR]

• Effects of Co-doping into ZrO 2 sol–gel films were investigated. • The surface of Co-doped ZrO 2 films showed well-ordered holes. • The E g of ZrO 2 reduces with Co doping. • Two sharp PL emission peaks were emerged at 335 and 373 nm in the PL spectra. • The magnetic behaviour of ZrO 2 film improved with Co doping. ZrO 2 is a fascinating metal oxide with rich physical phenomenon and promised applications. In this study, the effects of chemical doping with Co+2 ions on nanostructure, electronic, optical, photoluminescence (PL), and magnetic properties of Zr 1- x Co x O 2 thin films (x = 0.0, 0.05, 0.1, and 0.15) prepared by sol–gel spin-coating method were investigated. The films exhibited a tetragonal structure with crystallinity improved with Co doping. Pure ZrO 2 film showed a smooth surface morphology consisting of small particle size of 22 nm. The Co-doped ZrO 2 films exhibited well-ordered holes, and their size and number increased with Co doping up to x = 0.1 and then decreased at x = 0.15. Root-mean-square roughness increased from 1.1 nm for pure ZrO 2 to 16.5 nm for film x = 0.15. The Co ions in the films existed in a 2 + valence state. Energy band gap decreased with Co doping and had values of 4.40, 4.396, 4.392, and 4.170 eV for the films with x = 0.0, 0.05, 0.1, and 0.15, respectively. The PL spectra of films x = 0.00 and 0.05 are mainly comprised of two emission peaks; intense peak centred at 370 nm and broad peak centred about 500 nm. As the Co concentration increased, two intense and sharp emission peaks emerged at 335 and 373 nm. The films showed soft hysteresis loop, and their magnetization was enhanced with the increase of Co content. [ABSTRACT FROM AUTHOR]

The preparation and study of new pure M 0.90 Eu 0.1‐x Dy x Zr 4 (PO 4) 6 samples with M = Sr or Ba and x = 0, 0.025, 0.050 and 0.075 was described here in detail. Currently, the luminescent emission study of this type of samples based on their tunable with the type and content of ions in the host lattice is the subject of research. These samples were synthesized by a combustion route with urea addition, followed by treatment in a reducing N 2 /H 2 atmosphere. The effect of the strontium by barium substitution and the europium by dysprosium partial substitution on the structure, powder morphology, luminescent emission and magnetic behavior was investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), photoluminescence (PL) spectroscopy and magnetic measurements. X-ray diffraction patterns of the pure samples show diffraction maxima that can be assigned to a rhombohedral symmetry of space group R-3 with Z=6, compatible with a NASICON-type structure. FTIR spectra of the investigated samples show a broad band assignable to the different vibrational modes of the PO 4 3- groups. The experimental FTIR study was complemented with a theoretical study based on the SrZr 4 (PO 4) 6 structure and using different DFT methods and basis sets. Highly agglomerated spherical nanoparticles with an average particle size of about 18 nm that slightly increased with dysprosium content were found in TEM images. Broad emission bands were observed in the PL spectra of obtained samples, related to both the strontium by barium substitution and the different Eu2+/Eu3+/Dy3+ content. Magnetic susceptibility curves as a function of temperature confirm the presence of Eu2+ ions in Sr 0.90 Eu 0.1 Zr 4 (PO 4) 6 sample, and of Dy3+ ions with different Eu2+/Eu3+ ions content in the remaining M 0.90 Eu 0.1‐x Dy x Zr 4 (PO 4) 6 samples. [Display omitted] • (Sr/Ba)0.90Eu0.1-xDyxZr4(PO4)6 samples with M = Sr and Ba and with x = 0, 0.025, 0.050 and 0.075 were synthesized. • The effect of Sr by Ba substitution on the structure, size of particles and luminescent emission intensity was determined. • The effect of Eu by Dy partial substitution in the emission intensity was analyzed. • The presence of Dy3+ and Eu2+ ions with different Eu2+/Eu3+ relation was confirmed by magnetic susceptibility curves. [ABSTRACT FROM AUTHOR]

[Display omitted] • Single-step synthesis method: End products (Fe 2 O 3 and Fe 2 O 3) change depending on the precursor while maintaining the same conditions. • Low-cost, simple procedure that is good for large-scale synthesis. • Various oxides can be prepared using the specified preparation process. • Since nitrates and chlorides are abundant in industrial processes, this synthesis method can be modified to add value to the waste products produced. The two significant phases of iron oxide, namely, Hematite and Maghemite, have attracted the attention of scientists owing to their excellent magnetic and catalytic properties. Herein, we report a novel precursor salt-dependent single-step modified polyol method using the sol–gel auto combustion of metal nitrates or chlorides in ethylene glycol to synthesize magnetic alpha (α) and gamma (γ) Fe 2 O 3. The samples are then characterized to analyze the structural, morphological, electrical and magnetic properties. The XRD results show that the alpha and gamma Fe 2 O 3 exhibit hexagonal and cubic crystal structures, respectively. From the FESEM micrographs, the morphology changes are visible; for alpha Fe 2 O 3 a plate-like structure is seen, whereas the gamma Fe 2 O 3 particles exhibit a spherical morphology. The EDS spectrum indicates that the samples contain no impurity as the spectrum shows strong peaks for Fe and O. The Fe-O bond corresponding to stretching vibration is observed in the FTIR spectrum. The UV–Vis spectrum shows bandgap energy of 2.8 eV and 2.4 eV for alpha Fe 2 O 3 and gamma Fe 2 O 3, respectively. The surface of the prepared nanocomposite contains only Fe and O, which is confirmed from XPS analysis. The soft ferromagnetic behaviour of gamma Fe 2 O 3 and antiferromagnetic behaviour of alpha Fe 2 O 3 is evident from the magnetic measurements. The impedance analysis is also carried out, and the dielectric constant for alpha Fe 2 O 3 is 88, and that of gamma Fe 2 O 3 is 167. [ABSTRACT FROM AUTHOR]

LiKCuP 2 O 7 compounds were obtained by high temperature solid phase method. The crystal structure, thermal behavior, infrared spectroscopy, and magnetic behavior are discussed. [Display omitted] • The 3D framework of LiKCuP 2 O 7 consists of [CuP 2 O 7 ]2- layers, with Li+ and K+ cations filling between the layers. • Magnetic susceptibility measurements over a wide temperature range suggest that the compound is antiferromagnetic. • The structure comparison of the A–Cu–P–O system and the effect of cation size on its structures have been discussed. By the application of cation substitution with a site in A–Cu–P–O (A = alkali or mixed-alkali metals) system, a mixed-alkaline metal copper-containing phosphate LiKCuP 2 O 7 has been obtained. Single crystal X-ray diffraction analysis shows that LiKCuP 2 O 7 belongs to the P 2 1 / c space group and features a three-dimensional (3D) network constructed by LiO 4 , KO 9 , CuO 5 , P 2 O 7 units. Interestingly, the CuO 5 polyhedra are interlinked with P 2 O 7 units via vertex-sharing O atoms to form two-dimensional (2D) layers, where the Li+, K+ cations reside. In order to understanding the influence of cation size on the 3D networks as well as different dimensions of Cu–P–O frameworks, the structure comparisons in the A–Cu–P–O system have been discussed in detailed. Thermal behavior and infrared spectroscopy have been analysed. What is more, magnetic susceptibility measurements over a wide range of temperature exhibit the presence of antiferromagnetic behaviour. [ABSTRACT FROM AUTHOR]

• CaMn 0.9 Gd 0.1 O 3 fibres were obtained by LFZ under an external magnetic field (Hext) • Samples with CaMnO 3 major phase with some secondary phases were obtained. • Hext in grows direction favours phase alignment and magnetic properties. • Results show the viability to apply a Hext to other oxides tuning their properties. The perovskite-type calcium manganite exhibits interesting magnetic properties that can be tuned and enhanced by the laser floating zone (LFZ) method. This work explores, for the first time, the application of an external magnetic field during the LFZ growth of CaMn 0.9 Gd 0.1 O 3. The effects of the field direction on structural, microstructural, electrical and magnetic properties of the as-grown samples are evidenced, being observed an improvement on grain alignment and the magnetization (31.22 emu/g for 5 T at 5 K), when samples are grown under an external magnetic field in the growth direction, while the magnetic field applied in opposite direction a small improvement is observed. The results prospects to applied this process to other oxide systems for tuning their magnetic properties. [ABSTRACT FROM AUTHOR]

[Display omitted] • Effect of doping of iron on structural, optical and magnetic properties of CeO2 nanoparticle (nps) were prepared by co-precipitation method. • Explore the various physicochemical properties and characterization of XRD, XPS analysis and UV–vis spectrometer. • Magnetic studies were done for the Observed ferromagnetic results more support this phenomenon. CeO 2 , 0.5 Fe/CeO 2 , 1 % Fe/CeO 2 , 3 % Fe/CeO 2 , and 5 % Fe/CeO 2 nanoparticles (NPs) were prepared by simple chemical co-precipitation route. The structural, morphological, and compositional analysis of the prepared samples were studied. The pristine CeO 2 is diamagnetic whereas doped samples of Fe with CeO 2 enhance ferromagnetism in CeO 2 and the hysteresis area increases up to 5 mol % of Fe. Hence, to induce a ferromagnetic behaviour in CeO 2 NPs, 5 mol % of Fe is found to be optimum. The presence of Fe3+ as found from the XPS chemical analysis to acts as an electron acceptor and/or hole donor, facilitating longer charge carrier separation in Fe-doped CeO 2. [ABSTRACT FROM AUTHOR]

• Introduction to a method measuring temperature dependent magnetic properties. • Post-determination of primary microstructure of 50CrMo4 after QT heat treatment. • Precise hardness estimation choosing the right measurement parameters. • Correlation between the effect of different precipitations and magnetic properties. • Categorisation of the effect of eddy-currents on the B-H hysteresis. This work investigates the effect of different initial microstructures on the electromagnetic magnetisation curves/hysteresis of 50CrMo4 steel and technically pure iron introducing a novel measurement method. Surprisingly little is known about the relationship between microstructure and the magnetic properties, although this is of great importance for a better understanding and multi-physics modelling of induction heat treatment. Analysis of the magnetic hysteresis and Distortion Analysis of Magnetic Excitation (DAME) are important techniques to characterise magnetic behaviour of materials. To perform these measurements, a specific measurement setup based on excitation circuit/yoke with secondary coils was implemented. Using these methods, the characterization of the effect of mechanical properties (i.e.: hardness) and different microstructures on electromagnetic magnetisation curves/hysteresis is possible with high precision. The effect of the eddy-currents on the B-H hysteresis shows a systematic behaviour, which opens the possibility for a new kind of categorisation of these effects. DAME shows a closely linear relationship with the assumed precipitation size allowing indirect analysis of the microstructure, also at elevated temperatures. [ABSTRACT FROM AUTHOR]