Influence of the Alcoholic/Ethanolic Extract of Mangifera indica Residues on the Green Synthesis of FeO Nanoparticles and Their Application for the Remediation of Agricultural Soils

The green synthesis of iron oxide nanoparticles (FeO NP) has been investigated using the extract in absolute ethanolic and alcoholic solvents 96% from the peel of the mango fruit (Mangifera indica), thus evaluating the influence of the type of solvent on the extraction of reducing metabolites. A broad approach to characterization initially controlled by UV-vis spectrophotometry has been directed, the formation mechanism was evaluated by Fourier transform infrared spectroscopy (FTIR), the magnetic properties by characterization by Physical Property Measurement System (PPSM), in addition to a large number of techniques such as X-ray energy dispersive spectroscopy (EDS), X-ray diffraction (DRX), transmission electron microscopy (TEM/STEM), electron energy loss spectroscopy (EELS), and Z potential to confirm the formation of FeO NP. The results suggest better characteristics for FeO NP synthesized using 96% alcoholic solvent extract. The successful synthesis was directly proven in the removal of metals (Cr-VI, Cd, and Pb) as a potential alternative in the remediation of agricultural soils.

The Effects of La Doping on the Crystal Structure and Magnetic Properties of Ni2In-Type MnCoGe1−xLax (x = 0, 0.01, 0.03) Alloys

In this experiment, a series of MnCoGe1−xLax (x = 0, 0.01, 0.03) alloy samples were prepared using a vacuum arc melting method. The crystal structure and magnetic properties of alloys were investigated using X-ray diffraction (XRD), Rietveld method, physical property measurement system (PPMS), and vibrating sample magnetometer (VSM) analyses. The results show that all samples were of high-temperature Ni2In-type phases, belonging to space group P63/mmc (194) after 1373 K annealing. The results of Rietveld refinement revealed that the lattice constant and the volume of MnCoGe1−xLax increased along with the values of La constants. The magnetic measurement results show that the Curie temperatures (TC) of the MnCoGe1−xLax series alloys were 294, 281, and 278 K, respectively. The maximum magnetic entropy changes at 1.5T were 1.64, 1.53, and 1.56 J·kg−1·K−1, respectively. The respective refrigeration capacities (RC) were 60.68, 59.28, and 57.72J·kg−1, with a slight decrease along the series. The experimental results show that the doping of La results in decreased TC, basically unchanged magnetic entropy, and slightly decreased RC.

Characterization of a Novel Nanocomposite Film Based on Functionalized Chitosan–Pt–Fe3O4 Hybrid Nanoparticles

The development of organic—inorganic hybrids or nanocomposite films is increasingly becoming attractive in light of their emerging applications. This research focuses on the formation of a unique nanocomposite film with enhanced elasticity suitable for many biomedical applications. The physical property measurement system and transmission electron microscopy were used to analyze Pt–Fe3O4 hybrid nanoparticles. These nanohybrids exhibited magnetic effects. They were further exploited to prepare the nanocomposite films in conjunction with a chitosan-g–glycolic acid organic fraction. The nanocomposite films were then examined using standard techniques: thermogravimetric analysis, X-ray diffraction, Fourier transform infrared spectroscopy, and atomic force microscopy. Tensile strength testing demonstrated a significantly greater elastic strength of these nanocomposite films than pure chitosan films. The water absorption behavior of the nanocomposites was evaluated by measuring swelling degree. These nanocomposites were observed to have substantially improved physical properties. Such novel nanocomposites can be extended to various biomedical applications, which include drug delivery and tissue engineering.

Structure and magnetic properties of coprecipitated nickel-zinc ferrite doped rare earth elements of Sc, Dy, and Gd

This research is the basic study of temperature-sensitive ferrite characteristics prepared by coprecipitation with doping different typical sizes of rare earth elements. Ni 0.5 Zn 0.5 Re x Fe 2-x O 4 (NZRF) (X = 0.02, 0.05, 0.07 and 0.09) nanoparticles (NPs) doped by Sc, Dy and Gd prepared by chemical coprecipitation method. The structure and properties of Ni 0.5 Zn 0.5 Re x Fe 2-x O 4 were analyzed by various characterization methods. XRD results show that the grain size of Ni 0.5 Zn 0.5 Re x Fe 2-x O 4 is from 10.6 to 12.4 nm, which is close to the average grain size of 13.9 nm observed on TEM images. It is also found that the ferrite particles are spherical and slightly agglomerated in TEM images. FTIR measurements between 400 and 4000 cm -1 have confirmed the intrinsic cation vibration of the spinel structure. The concentrations of nickel, zinc, iron, and rare earth elements have been determined by ICP-AES, and all ions have participated in the reaction. The magnetic properties of Sc, Dy, and Gd 3+ doped NZRF NPs at room temperature are recorded by a physical property measurement system (PPMS-9). It is found that the magnetization can be changed by adding rare-earth ions. When X = 0.07, Gd 3+ doped Ni 0.5 Zn 0.5 Fe 2 O 4 (NZF) exhibits the highest saturation magnetization. The magnetic properties of NZGd 0.07 vary the most with temperature. The thermomagnetic coefficient of NZGd 0.07 nanoparticles stabilized to 0.18 emu/gK at 0-100℃. Hence, NZGd 0.07 with low Curie temperature and the high thermomagnetic coefficient can be used to prepare temperature-sensitive ferrofluid. All the samples exhibit very small coercivity and almost zero remanences, which indicates the superparamagnetism of the synthesized nanoparticles.

A study of structural, optical and ferromagnetic properties of sol-gel derived Cr and Fe co-doped CeO2 nanoparticles

The Cr and Fe co-doped CeO2 nanoparticles (Ce0.98−xCrxFe0.02O2: where x = 0, 0.01, 0.02, 0.03) were prepared by sol-gel method. Effects of additional Cr dopant on structural, optical and magnetic properties of Fe doped CeO2 nanoparticles have been investigated by X-ray diffraction (XRD), optical absorption spectra, Raman spectroscopy (Raman) and physical property measurement system (PPMS). XRD and Raman studied showed that all samples are single-phase of CeO2 original cubic fluorite crystal structure, Cr can readily be incorporated into the lattice of Fe doped CeO2 and no ferromagnetic secondary phase was found. With the increase of Cr doping concentration, the grain size and crystal quality decreases. The values of optical bandgap energy extracted from the absorption coefficient increase with the increase of Cr doping concentration. The PPMS studied show hysteresis phenomenon, which indicates that the samples have ferromagnetic properties at 300 K. With the increase of Cr content, the saturation magnetization increase obviously. Based on the results of XRD and Raman, it can be concluded that the ferromagnetism is the intrinsic property of the sample.

Effect of Pr, Mn Doping on the Structure and Properties of BiFeO3

The powders of Bi1-xPrxFeO3 (x = 0, 0.05, 0.1) and Bi0.95Pr0.05Fe1-yMnyO3 (y = 0.05, 0.1) were prepared by hydrothermal method. The effects of Pr and Mn doping content on the structure, morphology, magnetic, and photocatalytic properties of BiFeO3 (BFO) have been studied. X-ray diffraction (XRD) demonstrated that the compounds are distorted rhombohedral perovskite structure without any other heterogeneity and structural transition. Field emission scanning electron microscope (FESEM) reflected that the surface of compounds is a dense, agglomerated sphere, and the morphology changes with the addition of Pr, Mn. Energy spectrum analysis (EDS) shows that the Bi0.95Pr0.05Fe0.95Mn0.05O3 sample is mainly composed of 5 elements (Bi, Fe, O, Pr, Mn), and the atomic ratio matches the formula well. Integrating the vibrating sample magnetometer (VSM) into the physical property measurement system (PPMS-9) shows that the introduction of Pr3+and Mn2+ ions can enhance the magnetic properties of BFO at room temperature. In addition, doping with Pr3+ and Mn2+ ions can improve the photocatalytic performance of BFO, and with the increase of Mn2+ concentration, the photocatalytic performance of BFO first rises and then decreases, and its catalytic performance is getting better and better.

Zinc-bearing dust derived non-toxic mixed iron oxides as magnetically recyclable photo-Fenton catalyst for degradation of dye

In this paper, comprehensive utilization of hazardous zinc-bearing dust for preparation of non-toxic mixed iron oxides as the magnetically recyclable photo-Fenton catalyst for degradation of dye by a facile solid state reaction process was proposed. The as-prepared samples were characterized by X-ray diffraction (XRD), Raman spectra, Ultraviolet and Visible (UV-Vis) spectra and Physical Property Measurement System (PPMS), and the degradation performance of as-prepared catalysts was also tested and analyzed. The results show that spinel ferrite coexisted with or without Fe2O3 was the predominant phase in the as-prepared samples, which were confirmed by Raman analysis. The as-prepared samples presented high degradation efficiency (about 90%) of rhodamine B (RhB) in the presence of hydrogen peroxide (H2O2) with visible light irradiation, owing to the synergistic effect of photocatalyst reaction and Fenton-like catalyst reaction during the degradation process. The mixed iron oxides also presented stable structure and exhibited excellent reusability with the degradation efficiency of 87% after the fifth cyclic reuse. Importantly, the heavy metals in the zinc-bearing dust could be fixed in the stable spinel structure. This paper could provide a simple approach for comprehensive utilization of zinc-bearing dust to synthesize non-toxic mixed iron oxides as the magnetically recyclable photo-Fenton catalyst for degradation of dye.

Superparamagnetic Magnetite Nanotubes Synthesized by Template-Assisted Sol–Gel Autocombustion

Magnetite nanotubes with an average diameter of about 140 nm were synthesized by an AAO templateassisted sol–gel autocombustion method. The entire synthetic process is convenient, low-cost and nontoxic. The crystalline structure of the magnetite nanotubes was investigated by X-ray diffraction. From the diffraction pattern, we conclude that pure phase magnetite nanotubes were obtained. Tubular morphologies of the products were observed by transmission electron microscope. The as-prepared magnetite nanotubes have a high aspect ratios. The magnetic properties of the nanotubes were measured by a Physical Property Measurement System. The magnetic measurements indicate that the nanotubes have superparamagnetic characteristic at room temperature, and have ferromagnetic characteristic with a coercivity of about 518 Oe at 5 K. The blocking temperature TB of the nanotubes are measured to be 95 K. The as-prepared magnetite nanotubes may find potential applications in bio-medicine.

Law of Approach to Magnetic Saturation in Nanocrystalline Pr2Co7Cx(x≤1): Effects of Carbonation

We report on the effect of Carbon insertion on the microstructure and magnetic properties of nanocrystalline Pr2Co7Cx([Formula: see text]). The Pr2Co7Cx were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and physical property measurement system (PPMS9) Quantum Design. Mean field theory was utilized to depict the temperature dependence of magnetization and deduce the exchange interactions. The approach to saturation magnetization was as well used. The results were interpreted in the framework of random magnetic anisotropy model. From such analysis, some fundamental parameters were extracted.

Trilayer Films of YBa2Cu3O7−x/LaAlO3/YBa2Cu3O7−x with Superconducting Properties Prepared via Sol-Gel Method

The YBa2Cu3O7−x/LaAlO3/YBa2Cu3O7−x (YBCO/LAO/YBCO) heterogeneous trilayer film structures were prepared on the LaAlO3 (001) single-crystal substrate via the sol-gel method. The characteristics of the phase, orientation, and superconducting properties were studied via an X-ray diffractometer and a comprehensive physical property measurement system. The results show that when the LAO layer was thin (<40 nm), the trilayer films were relatively pure and had a high c-axis orientation. When the nominal thickness of the LAO layer increased to 70 nm, non-c-axis oriented grains started to appear in the trilayer film. In this case, the top and bottom YBCO layers exhibited superconducting properties, and the resistance was found to be zero at 80.1 and 72.5 K, respectively. In addition, for the YBCO/LAO (40 nm)/YBCO structure, the intermediate LAO layer was too thin to completely cover the surface of the underlying YBCO. This resulted in point contact and micro-bridge contact in several micro-regions, thus forming a weak connection and exhibiting a current-voltage (I–V) characteristic similar to the direct-current (DC) Josephson effect. On the other hand, for the YBCO/LAO (70 nm)/YBCO structure, the thicker LAO layer could completely cover the underlying YBCO surface, which could isolate the superconducting current between the YBCO layers.