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In this research paper, we have reported the thermal, structural, magnetic and optical properties of unsubstituted and aluminum substituted zinc ferrite nanoparticles. These substituted and unsubstituted ferrite nanoparticles were prepared by cost effective co-precipitation method. The co-precipitated unannealed nanoparticles of the typical sample were subjected to thermogravimetric analysis (TGA) to probe the annealing temperature. The X-rays diffraction (XRD) technique was used for the determination of structural parameters. XRD patterns of all compositions of Al x ZnFe 2-x O 4 nanoparticles confirmed the FCC structure of these spinel ferrite nanoparticles. Besides the main crystal structure determination, many other lattice parameters and their variations with respect to increased Al3+ contents in ZnFe 2 O 4 were also calculated from XRD data and have been discussed in detail in this article. The morphology of the synthesized materials has been studied by scanning electron microscopy (SEM) and average particles size found < 100 nm. The variation in electrical and magnetic parameters with increased Al3+ contents was studied in detail. The analysis of magnetic properties concluded that the prepared nanoparticles have good magnetic properties. At the end the optical studies of the nanoparticles proved that these spinel ferrites also have photocatalytic applications. The photocatalytic degradation of methylene blue in the presence of these samples has been studied and discussed. The ferrites particles could be separated from contaminated water simply by magnetic bars. Therefore these particles can be used and recycled easily for photocatalytic applications. The aim of work was to study the structural, electrical, magnetic and catalytic behavior of the material. [ABSTRACT FROM AUTHOR]

The present study was conducted to evaluate the effects of storage time and temperature on physicochemical and sensory properties and to measure the spoilage of pasteurized fluid milk stored at different temperatures via nanoparticles on pasteurized fluid milk. The mean values for pH of milk samples decreased (from 6.81 to 6, 5.46, and 4.37), acidity increased (10%, 21%, and 35%), fat contents decreased (13%, 24%, and 32%), protein contents decreased (7%, 18%, and 24%), lactose contents decreased (5%, 7%, and 12%), and total free fatty acids increased (14%, 19%, and 27%) respectively at 4°C, 7°C, and 10°C. Similarly, the score of sensory parameters like aroma, taste, and overall acceptability decreased 16%, 23%, and 45%; 31%, 43%, and 52%; and 33%, 42%, and 53% respectively in linear pattern along with increasing the time and temperature. The L* values were non-significantly changed or decreased with mean values of 64.82 ± 0.08 to 64.13 ± 0.07 at 4°C and significantly with 64.81 ± 0.03 to 63.87 ± 0.07 and 64.77 ± 0.02 to 61.43 ± 0.05 at 7°C and 10°C respectively at 0–19th day of milk storage. During storage, the pasteurized milk stored at all temperatures 4°C, 7°C, and 10°C showed that a* value non-significantly decreased from 48.69 ± 0.18 to 48.63 ± 0.18, 48.74 ± 0.14 to 48.57 ± 0.11, and 48.68 ± 0.18 to 47.97 ± 0.07 respectively. Values of b* decreased non-significantly at 4°C and 7°C with the values of −17.56 ± 0.23 to −18.58 and −17.54 ± 0.25 to −19.85 ± 0.85 but significantly decreased at 10°C from −17.56 ± 0.23 to −43.22 ± 0.11. The results suggested that pasteurized milk can be kept for 17–19 days at 4°C but this shelf life drastically reduced at 7°C and 10°C. Color of nanoparticles was significantly changed from pink to dark blue from 14th day of storage onwards to the end at 10°C. Conclusively, nanoparticles can be used for the rapid and at the post-spoilage measurement of pasteurized milk. [ABSTRACT FROM AUTHOR]

Abstract In this work erbium (Er3+) substituted cobalt zinc ferrite having general formula Co 0.70 Zn 0.30 Er x Fe 2-x O 4 (x = 0, 0.01, 0.02, 0.03, 0.04, 0.05) were fabricated using micro-emulsion technique. The substitution of Er was done for the purpose of tuning the optical band gap. Er+3 substituted nanoparticles were annealed at 700 °C for 7 h. A typical composition of Co 0.70 Zn 0.30 Er x Fe 2-x O 4 was utilized to make the nanocomposites material with reduced graphene oxide (rGO), that was prepared by facile chemical route. The main purpose of graphene was to enhance the conductivity of ferrite particles. All these ferrite particles and a composite were characterized by X-rays diffraction (XRD), UV–Visible spectroscopy and SEM for structural elucidation and morphology studies. Single phase spinel structure was confirmed by XRD analysis and crystallized size calculated by Scherer formula was found in the range 35–60 nm. SEM confirmed the well dispersed ferrite particles among graphene sheets. All the Er-substituted ferrite particles were subjected to dielectric parameters study. One typical composition of Co 0.70 Zn 0.30 Er x Fe 2-x O 4 particles and its composites with rGO were utilized for photocatalysis study using methylene blue as model organic compound in the presence of visible light. Current-voltage (I-V) measurements of ferrites nanoparticles and their composites with graphene were also studied. The results of all these techniques were agreed with each other and suggested the various potential applications of these nanoparticles. Highlights • Rare earth Er3+-substituted Cobalt-Zinc Nano-ferrites were prepared. • XRD confirmed the FCC structure of all compositions. • Graphene@ ferrite composites exhibited better photocatalytic properties. [ABSTRACT FROM AUTHOR]

In this article, we have reported an effective, rapid as well as economical Er3+ substituted Ni 0.4 Co 0.6 Fe 2 O 4 ferrite nanoparticles synthesized via surfactant-assisted co-precipitation route. The synthesized nanoparticles were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), dielectric properties, current-voltage (I–V) measurements, and vibrating sample magnetometry (VSM). XRD and FTIR confirmed the face-centered (FCC) spinel structure of all compositions of the synthesized spinel ferrite nanoparticles. The deviations in the lattice constant granted with the variation in size of the guest (Er3+) and host (Fe3+) cations. These ferrites were also subjected for electrical, magnetic and dielectric investigations. I–V measurements showed that resistivity values decreased from 6.20 × 107 Ω cm to 0.03 × 107 Ω cm with the increased Er3+ contents. Saturation magnetization increased from 35.99 to 39.95 emu/g. This high value of saturation magnetization suggested the possible utilization of such ferrites for practical applications such as microwave and recording devices fabrication. Interestingly, the magnetic and dielectric properties of nickel-cobalt ferrite nanoparticles showed ample improvement upon Er3+ substitution. The results clearly indicate the potential of Er+3 substituted spinel ferrite particles in various advanced technological devices fabrication. [ABSTRACT FROM AUTHOR]

A multipurpose, environment-friendly, and effective catalyst for control of environmental contaminants is an enduring interest in recent years. In the present study, lanthanum substituted spinel ferrite (La x MnFe 2-x O 4) nanoparticles were synthesized using an eco-friendly, low cost-effective reverse-micelle synthesis strategy. Thermal analysis was done to annualize the annealing temperature of prepared precipitates. X-ray diffraction (XRD) study revealed the well-defined cubic spinel structure of La x MnFe 2-x O 4 with the presence of a very minute secondary phase by the introduction of La3+ ion. Fourier transform infrared spectroscopy (FTIR) study confirmed the M − O metal-oxygen bond stretching at tetrahedral and octahedral sites. Surface morphology analyzed by field emission scanning electron microscopy (FESEM) revealed the narrow size distribution having nanoparticles size of nearly 60 nm. From the bandgap study, an enhanced redshift of 2.40 eV directed its semiconductor photocatalysis behavior. The degradation efficiency of pristine MnFe 2 O 4 and La3+ ion substituted MnFe 2 O 4 material was investigated using a contaminant crystal violet dye. Higher degradation efficiency, kinetic investigation smart degradation mechanism, and simple recovery suggested that the newly designed La3+ ion substituted MnFe 2 O 4 photocatalytic material is best for environmental remediation. [ABSTRACT FROM AUTHOR]

• Dy x MnFe 2- x O 4 nanoparticles decorated over mesoporous silica were synthesized. • High BET surface area of catalyst responsible for excellent adsorption. • The prepared catalyst also exhibited good photocatalytic activity. An efficient, environment-friendly and economical catalyst to control contaminants of environment is an enduring interest in recent years. In this study, a new composite, Dy x MnFe 2- x O 4 nanoparticles decorated over mesoporous silica was synthesized and utilized for removal of organic pollutant. Highly crystalline nature of Dy x MnFe 2- x O 4 nanoparticles and amorphous nature of material was confirmed by XRD (X-ray diffraction) technique. Infrared spectra of fabricated material before and after adsorption of dye molecules evidenced the successful adsorption of dye molecules by fabricated adsorbent. From field emission scanning electron microscopic (FESEM) images of Dy3+ substituted MnFe 2 O 4 composite with mesoporous silica, it was clearly observed that ferrite particles of size 20−30 nm were decorated on the surface of mesoporous silica particles and distributed well over spherical silica balls homogeneously. Its magnificent mesoporous nature was revealed from BET (nitrogen adsorption-desorption measurements) analysis. Surface area, pore volume and average pore size was found 387.95 m2/g, 0.390 cm3/g and 4.02 nm respectively. Tri-modal pore size distribution showed its effective utilization in adsorption. The abundant (Si OH) hydroxyl groups of mesoporous silica, the broad diffraction hump of silica depicted its superior loading capacity of target molecular specie inside its porous network. From band gap analysis, a red shift of 2.43 eV exhibited semiconductor photocatalysis of Dy x MnFe 2- x O 4 nanoparticles. Degradation efficiency of bare MnFe 2 O 4 , Dy x MnFe 2- x O 4 and mesoporous silica-based composite was tested using crystal violet dye. Its explored adsorption-photocatalysis synergy, degradation mechanism, kinetic investigation, easily recovery and remarkable recycling ability suggested that the new fabricated composite is best for environmental remediation. [ABSTRACT FROM AUTHOR]