Vibrating Sample Magnetometer Techniques Research Articles

Synthesis and Evaluation of Novel Ternary MgFe2O4/CuO/TiO2 Nanocomposite for Visible Light Photodegradation of Malachite Green Dye

Novel ternary MgFe2O4/CuO/TiO2 nanocomposite was synthesized using the sol-gel method at low temperatures. The XRD, FTIR, SEM-EDX, TEM, UV-visible DRS and VSM techniques were used to characterize the structure, shape, optical, morphology and magnetic properties. The XRD examination revealed typical peaks in nanocomposites, including the anatase phase of TiO2 with an average diameter of 9 nm, consistent with the TEM data. The SEM morphology examinations revealed spherical particles, while EDAX analysis indicated the corresponding components (Fe, Ti, O, Mg and Cu) in the prepared nanocomposites. The UV-DRS measurements revealed that the synthesized nanocomposite has a band-gap energy of 2.30 eV. The vibrating sample magnetometer (VSM) was used to trace the M-H loop of MgFe2O4, yielding magnetic parameters such as saturation magnetization (Ms). The catalytic activity of the as-prepared sample was examined by the degradation of malachite green dye under visible light and UV irradiations. The photocatalytic studies demonstrated that MgFe2O4/CuO/TiO2 nanocomposite showed 100% degradation efficiency towards malachite green dye. Under visible light and UV irradiations, the synthesized MgFe2O4/CuO/TiO2 sample with a molar ratio of 0.8:0.1:0.1 demonstrated good catalytic efficiency. The antibacterial activity investigations were done against Gram-negative Escherichia coli, Klebsiella pneumonia, Gram-positive Staphylococcus aureus and Bacillus subtilis bacteria utilizing nanocomposites.

Insight into efficient photocatalytic degradation of norfloxacin over a simple, economical biochar-based magnetic photocatalyst under solar illumination: a statistical and experimental approach.

The transformation of residual agricultural solid waste into an efficient value-added carbon product has been an ongoing strategy for solid waste management and a sustainable economy. Meanwhile, the upsurgence of antibiotic contamination in water bodies due to their inadvertent use poses a serious threat to human health and leads to antimicrobial resistance. Hence, to neutralize two evils in one stroke simultaneously, a simple, easy, and cost-effective pea shell-based magnetic photocatalyst (PSMC) has been synthesized and characterized by XRD (X-ray diffraction), VSM (vibrating sample magnetometer), XPS (X-ray photoelectron spectroscopy), TGA (thermogravimetric analysis), and FTIR (Fourier-transform infrared) spectroscopy techniques. Batch experimental studies revealed that PSMC efficiently eliminates norfloxacin (91.3%) within 180min from wastewater and mineralizes it into innocuous products at optimum parameters of norfloxacin concentration of 20mg/L, catalyst dosage of 15mg, and pH 3.5. Additionally, statistical parameters for the photodegradation of NX obtained from ANOVA by applying the Box-Behnken design are in close agreement with batch experiment parameters. PSMC has surplus advantages of facile recovery for recycling up to seven consecutive cycles by an external magnet and efficacy in natural solar light, making it cost-effective and economical. Radical scavenging studies revealed that O2•- and OH• were the potent reactive species in the photocatalytic degradation process.

Anticancer efficacy of magnetite nanoparticles synthesized using aqueous extract of brown seaweed Rosenvingea intricata, South Andaman, India

Cancer is a global issue and hence various efforts are being made. Iron oxide is considered a significant biochemical agent in the biomedical arena for cancer treatment. Marine macroalgae-mediated iron oxides especially, magnetite (Fe3O4) nanoparticles (NPs) are a prospective alternative to diagnose and treat cancer owing to their fluorescent and magnetic properties. We intend to appraise the usability of the aqueous extract of Rosenvingea intricata (R. intricata) in Fe3O4 NPs synthesis and to study their cytotoxic effects against human hepatocarcinoma (Hep3B) and pancreatic (PANC1) cancer cells. In the present study, R. intricata were collected from the coastal region of South Andaman, India. Aqueous extracts of R. intricata were utilized to synthesize Fe3O4 NPs via the co-precipitation method. Phycosynthesized Fe3O4 NPs exhibited wide peak at 400–600 nm from ultraviolet–visible diffused reflectance spectroscopic analysis which validated the formation of NPs. Band edge emission peak at 660 nm in fluorescent spectra confirmed the quantum confinement in Fe3O4 NPs. Fourier transform infrared spectroscopy confirmed the role of R. intricata as a capping and reducing agent with functional groups such as O–H, C–H, C=O, N=O, C=C, C–O, C–N, and C–S arising from amino acids, polysaccharides, aliphatic hydrocarbons, esters, amides, lignins, alkanes, aliphatic amines, and sulfates. Physicochemical properties such as crystallite size (14.36 nm), hydrodynamic size (84.6 nm), irregular morphology, elemental composition, particle size (125 nm), crystallinity, and saturation magnetization (0.90007 emu/g) were obtained from x-ray diffractometer, dynamic light scattering, scanning electron microscopy, energy dispersive x-ray spectrometer, high-resolution transmission electron microscopy, selected area electron diffraction and vibrating sample magnetometer techniques, respectively. The cell viability showed dose-dependent cytotoxic effects and enhanced the apoptosis against Hep3B and PANC1 cancer cells. R. intricata extract capped Fe3O4 NPs could be the most appropriate and effective nanomaterial for cancer treatment and management.

Salvia officinalis leaf extract-stabilized NiO NPs, ZnO NPs, and NiO@ZnO nanocomposite: Green hydrothermal synthesis, characterization and supercapacitor application

AbstractIn this study, NiO nanoparticles (NiO NPs) and NiO@ZnO nanocomposite were synthesized for the first time using a Salvia officinalis (S. officinalis) extract-assisted hydrothermal process. The S. officinalis leaf extract served as a natural reducing and capping agent. The synthesized NiO NPs, ZnO NPs, and NiO@ZnO nanocomposite were thoroughly characterized using various techniques, including Fourier-transform infrared spectroscopy (FT-IR), ultraviolet–visible spectroscopy (UV–Vis), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), energy-dispersive spectrometry (EDS) mapping, vibrating sample magnetometer (VSM), and cyclic voltammetry (CV) analysis. The direct and indirect band gap energies of NiO NPs, ZnO NPs, and NiO@ZnO were found to be 3.00, 2.28, and 2.71 eV, and 2.63, 1.91, and 2.23 eV, respectively. The crystallite sizes were analyzed using PXRD spectra through Scherrer and Williamson–Hall (W–H) methods. TEM analysis revealed that the average particle sizes of NiO NPs, ZnO NPs, and NiO@ZnO were 16.0, 207.5, and 31.0 nm, respectively. The magnetic properties of all nanomaterials were assessed via the VSM technique. Specific capacitance (Cs) values, determined from CV voltammograms, were 196.8, 632.4, and 785 Fg-1 at a scan rate of 25 mVs-1 for NiO NPs, ZnO NPs, and NiO@ZnO, respectively. These findings suggest that the green-synthesized NiO@ZnO nanocomposite holds significant potential as a high-performance electrode material for supercapacitor applications.

Using Silica Shell to Improve the Surface of Magnetite Prepared by Biosynthesis Method

The combined of superparamagnetic properties (magnetite) and surface characteristics (silica), can produce structures with multiple capacities. The preparation of such magnetite-silica core-shell nanoparticles involves high costs in their execution and longer time. In this work, Fe3O4@SiO2 CSNPs were synthesized in two stages to control their size and the possibility of adjusting their characteristics. First, Fe3O4 NPs were synthesized by a green method using carob leaf extract, then coating the magnetite nanoparticles with a silica layer was done by using Tetraethylorthosilicate (TEOS) as a silica precursor. X-ray diffraction (XRD), transmission electron microscopy (TEM), atomic force microscope (AFM), Fourier transform infrared, and vibrating sample magnetometer techniques were used to characterize the magnetite-silica CSNPs. TEM images confirms that Fe3O4NPS and Fe3O4@SiO2 CSNPs synthesized had a spherical shape and were within 9 and 17 nm. The average crystallite sizes of the synthesized Fe3O4 NPs and Fe3O4@SiO2CSNPs were found to be 17.8 nm and 20 nm. The VSM indicated that the magnetization decreased due to being coated with silica.

Magnetic graphene oxide functionalized dimercaptosuccinic acid/putrescine as a selective and stable solid-phase extraction adsorbent for preconcentration and speciation of arsenic (III) in water samples

ABSTRACT It is challenging for environmental scientists to identify the trace value of arsenite (As(III)) as an essential hazardous material in the presence of arsenate (As(V)) and other metal ions. This paper proposes a method of magnetic solid-phase extraction (MSPE) for the trace analysis of As(III) using magnetite graphene oxide (MGO) covalently functionalised with dimercaptosuccinic acid (DMSA) and putrescine (PUT). The hydrothermally synthesised MGO/DMSA-PUT adsorbent was carefully characterised by using energy-dispersive X-ray spectroscopy analysis, Fourier transform infrared, dynamic light scattering, scanning electron microscopy, zeta potential analyser, X-ray diffraction, and vibrating sample magnetometer techniques in detail. Maximum adsorption capacity of MGO/DMSA-PUT for As(III) was determined 144 mg g−1 which considerably improved vs. graphene oxide with the adsorption capacity of 54.8 mg g−1. Sample pH of 6 with a volume of 50 mL, contact time of 5 minutes, initial concentration of 50 μg L−1, adsorbent dosage of 0.1 g and volume of eluent 3 mL were obtained as the optimised parameters for the developed MSPE procedure. According to experimental data obtained with hydride generation atomic absorption spectroscopy, the linear range and detection limit of the proposed method for As(III) measurement was found to be 0.4–5000 µg L−1 and 9.914 ng L−1, respectively. According to experimental results, a preconcentration limit (PL) of 1.72 µg L−1 was achieved for As(III), corresponding to a preconcentration factor of 965. Statistical analysis of standard reference materials confirmed the accuracy of the method against systematic and constant errors (>95% recovery with <5% RSD). Because of the selectivity of MGO/DMSA-PUT towards the As(III), the developed MSPE procedure is capable for successful speciation and determination of As(III) in water samples with satisfactory analytical results.

A novel and efficient boron-containing magnetic catalyst based on graphene oxide (GO-Fe3O4-BFn) for synthesis of pyrazole and pyranopyrazole derivatives

The creation of non-toxic acidic catalysts has benefited greatly from the immobilization of acidic materials on solid substrates. In the present work, a novel and capable magnetically Lewis acid catalyst based on graphene oxide (GO) was introduced for the synthesis of pyrazole derivatives. The new catalyst was prepared as a heterogeneous Lewis acid composite by immobilization on BF3 on GO-Fe3O4. The magnetic and recoverable catalyst was characterized by FT-IR (Fourier‑Transform Infrared Spectroscopy), FESEM (Field Emission Scanning Electron Microscopy), XRD (X‑Ray Diffraction), EDS (Energy-Dispersive X-Ray Spectroscopy), ICP (Inductively Coupled Plasma), VSM (Vibrating Sample Magnetometer) and TGA (Thermogravimetry Analysis) techniques. Catalytic activity of the GO-Fe3O4–BFn checked out in the synthesis of pyrazole (3a-3f) and 2,4-dihydropyrano[2,3-c] pyrazole (8a-8f) derivatives under mild conditions. Pyrazole and pyranopyrazol derivatives were synthesized in desirable yield in the presence of our new catalyst. High surface area, chemical and thermal stability, good selectivity, high reactivity with easily magnetically separation are some of advantageous of our catalyst. The catalyst can also be recycled for several times without reducing its catalytic efficiency. Furthermore, molecular docking studies were performed to predict the interaction mode of the synthesized compounds toward the EGFR kinase as a possible target.

Facile and green synthesis of recyclable, environmentally friendly, chemically stable, and cost-effective magnetic nanohybrid adsorbent for tetracycline adsorption

Antibiotic contamination of water sources, particularly tetracycline (TC) contamination, has emerged as one of the global issues that needs action. In this research, ZnCoFe2O4@Chitosan (Ch) as a magnetic nanohybrid adsorbent was synthesized using the microwave-assisted co-precipitation method, and their efficiency for the TC adsorption process was investigated. FESEM (Field Emission Scanning Electron Microscope), EDX (Energy Dispersive X-ray), Mapping and line Scan, XRD (X-Ray Diffraction), FTIR (Fourier Transform Infrared Spectrometer), VSM (Vibrating Sample Magnetometer), Thermogravimetric analysis (TGA) and BET (Brunauer Emmett Teller) techniques were used to check and verify its physical and chemical properties. The removal of TC via the adsorption process from synthetic and real wastewater samples was investigated. The factors determining the TC adsorption process, comprising tetracycline concentration (5–30 mg/L), adsorbent dosage (0.7–2 g/L), contact time (2–45 min), and pH (3–11), were evaluated. The removal effectiveness for the synthetic sample and the real wastewater sample was 93 % and 80 %, respectively, under the ideal TC adsorption process parameters of pH 3, adsorbent dosage 1 g/L, TC initial concentration 5 mg/L, and contact time 30 min. According to kinetic and equilibrium studies, the adsorption of TC by ZnCoFe2O4@Ch follows pseudo-second-order kinetics and the Freundlich isotherm. Additionally, it was determined through the analysis of thermodynamic data that the process of exothermic adsorption is spontaneous and is followed by a decrease in disorder (ΔH = −15.16 kJ/mol, ΔS = −28.69 kJ/mol, and ΔG = −6.62 kJ/mol). After five cycles of recovery and regeneration, the ZnCoFe2O4@Ch magnetic nanocomposite was able to remove 65 % of the TC pollutant and had good chemical stability. The results showed that the magnetic nano-adsorbent ZnCoFe2O4@Ch is a novel magnetic nano-adsorbent with high adsorption capacity that can be utilized to eliminate pharmaceutical contaminants from aqueous solutions.

Structural, Optical, and Magnetic Properties of Pure and Ni-Fe-Codoped Zinc Oxide Nanoparticles Synthesized by a Sol-Gel Autocombustion Method.

Pure and Ni-Fe-codoped Zn1-2xNixFexO (x = 0.01, 0.02, 0.03, and 0.04) nanoparticles were effectively synthesized using a sol-gel autocombustion procedure. The structural, optical, morphological, and magnetic properties were determined by using X-ray diffraction (XRD), ultraviolet-visible (UV-vis), scanning electron microscopy, and vibrating sample magnetometer techniques. The XRD confirmed the purity of the hexagonal wurtzite crystal structure. XRD analysis further indicated that Fe and Ni successfully substituted the lattice site of Zn and generated a single-phase Zn1-2xNixFexO magnetic oxide. In addition, a significant morphological change was observed with an increase in the dopant concentration by using high-resolution scanning electron microscopy. The UV-vis spectroscopy analysis indicated the redshift in the optical band gap with increasing dopant concentration signifying a progressive decrease in the optical band gap. The vibrating sample magnetometer analysis revealed that the doped samples exhibited ferromagnetic properties at room temperature with an increase in the dopant concentration. Dopant concentration was confirmed by using energy-dispersive X-ray spectroscopy. The current results provide a vital method to improve the magnetic properties of ZnO nanoparticles, which may get significant attention from researchers in the field of magnetic semiconductors.

Magnetic and Magnetostrictive Properties of Sol-Gel-Synthesized Chromium-Substituted Cobalt Ferrite.

Chromium (Cr)-doped cobalt ferrite nanoparticles were synthesized using a sol-gel autocombustion method, with the chemical formula CoCrxFe2xO4. The value of x ranged from 0.00 to 0.5 in 0.1 increments. X-ray diffraction analysis confirmed the development of highly crystalline cubic spinel structures for all samples, with an average crystallite size of approximately 40 to 45 nm determined using the Scherrer equation. Pellets were prepared using a traditional ceramic method. The magnetic and magnetostrictive properties of the samples were tested using strain gauge and VSM (vibrating sample magnetometer) techniques. The results of the magnetic and magnetostrictive tests showed that the chromium-substituted cobalt ferrites exhibited higher strain derivative magnitudes than pure cobalt ferrite. These findings indicated that the introduction of chromium into the cobalt ferrite structure led to changes in the material's magnetic properties. These changes were attributed to anisotropic contributions, resulting from an increased presence of Co2+ ions at B-sites due to the chromium substitutions. In summary, this study concluded that introducing chromium into the cobalt ferrite structure caused alterations in the material's magnetic properties, which were explained by changes in the cationic arrangement within the crystal lattice. This study successfully explained these alterations using magnetization and coercivity data and the probable cationic dispersion.

Effect of magnetic field on the thermal conductivity and viscosity of magnetic manganese Oxide/Ethylene glycol Nanofluids: An experimental and ANFIS approach

The magnetic manganese oxide (Mn3O4) nanowires were prepared by using solvothermal method and characterized by using X-ray diffraction, X-ray photoelectron spectroscopy and vibrating sample magnetometer techniques. The stable Mn3O4/ethylene glycol nanofluids were prepared in the particle volume loadings ranging from 0 % to 1.25 %. The thermal conductivity and viscosity were measured in the temperatures ranging from 20 °C to 60 °C and in the magnetic field ranging from 0 to 2350 Gauss. An adaptive neuro-fuzzy inference system (ANFIS) algorithm was used to correlate the measured thermal conductivity and viscosity values. Experiments were shown that at ϕ = 1.25 % vol. of nanofluid, the thermal conductivity is enhanced by 18.8 % at 60 °C; moreover, the viscosity of ϕ = 1.25 % vol. of nanofluid is raised by 89.4 % at 20 °C, compared to base fluid. Further results showed that, nanofluid at ϕ = 1.25 % with magnetic field of 1150 Gauss, and at 60 °C the thermal conductivity is enhanced by 52.4 %; however, nanofluid at ϕ = 1.25 % with magnetic field of 1450 Gauss, and at 20 °C, the viscosity is enhanced by 207 % against the same nanofluid without magnetic field. The used algorithm was successfully predicted the target data with a root mean square error of 0.0013744 and 0.311183 for thermal conductivity and viscosity data.

Prompt antibacterial activity of silver nanoparticle decorated on HAp embedded NiFe2O4 nanocomposite (NiFe2O4@HAp-Ag) against pathogenic strains and investigation of its photocatalytic activity towards degradation of antibiotics

Local bacterial infection in clinics is still a difficult task and poses serious health threats to human. Systemic antibiotic administration typically results in negative side-effects and bacterial resistance and only has transient antibacterial activity. Several biomedical applications immensely prefer modified hydroxyapatite with excellent biocompatibility and antibacterial characteristics. Herein, we fabricate hydroxyapatite-embedded NiFe2O4 using in situ hydrothermal method and used as a support for silver nanoparticle onto its surface to achieve an effective biological response. The properties of the as-synthesized materials were characterized using several spectroscopic techniques which include X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy, ultraviolet–diffuse reflectance spectroscopy spectroscopy, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, high resolution transmission electron microscopy. In addition, the magnetic behavior of these nanocomposites was examined using the vibrating sample magnetometer technique. This ternary nanocomposite exhibits potent antimicrobial activity against both Gram-negative bacteria (Pseudomonas aeruginosa and klebsiella pneumoniae) as well as Gram-positive bacteria (Staphylococcus aureus and Bacillus cereus). The MIC or minimum inhibitory concentration, MBC or minimum bactericidal concentration, the disc diffusion, bacterial growth rate, and inhibition rate tests were utilized for the examination of the antimicrobial effect of this synthesized nanocomposite against pathogenic strains. Along with this, we have also investigated its photocatalytic activity toward degradation of cefixime antibiotic under solar light and it shows excellent photodegradation performance. The fabricated nanocomposite demonstrated high reusability with good photostability. Notably, using magnetic decantation this prepared nanocomposite can be easily eliminated from the disinfected medium.

Structural and magnetic analysis of Cd-Zn spinel ferrite nanoparticles

Sol-gel auto-combustion synthesis technique was employed to synthesize Cd-Zn ferrite nanoparticles with composition Zn1-xCdxFe2O4, where 0.0 ≤ x ≤ 1.0. The physical properties of prepared samples were inspected by using x-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR) and vibration sample magnetometer (VSM) techniques. XRD analysis confirmed the formation of Cd-Zn spinel nanoferrites with an increase in experimental lattice constant from 8.37 Å to 8.74 Å for zinc and cadmium ferrite samples, respectively. Variation of tetrahedral and octahedral hopping lengths, crystallite size, microstrain and dislocation density with Cd-content has been investigated and elucidated. SEM micrographs showed agglomeration of nearly-spherical grains that increased in size with Cd-content increase. FTIR analysis confirmed the existence of the characteristic tetrahedral and octahedral stretching vibrations of metal ion and oxygen complex in the range 429–558 cm−1. VSM measurements revealed a tuning in coercivity to higher values and a decrease in saturation magnetization as Cd-content increased. The calculated cations distribution, bond lengths, bond angles and interionic distances between cations at tetrahedral and octahedral sites attribute the observed decrease in saturation magnetization to weak interaction between cations in the two sites.

Biomass juncus derived carbon modified with Fe3O4 nanoparticles toward activating peroxymonosulfate for efficient degradation of tetracycline

In this work, Fe3O4 nanoparticles anchored biomass juncus derived carbon (Fe3O4@JDC) was developed as a highly efficient heterogeneous peroxymonosulfate (PMS) activator to degrade organic pollutants. As-prepared catalyst was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and vibrating sample magnetometer techniques. High loading and good dispersion of Fe3O4 nanoparticles on JDC lead to excellent degradation performance for tetracycline (90.2 %, 60 min) and other pollutants (above 80 %), and the reaction rate constant (k) is 3.73 times (0.0384 min−1) than that of pure JDC (0.0103 min−1) in the presence of PMS. Additionally, chemical oxygen demand (COD) removal rate of Fe3O4@JDC/PMS system (64.7 %, 60 min) is best than other systems (JDC system, JDC/PMS system, etc.). The quenching tests and electron paramagnetic resonance (EPR) data further demonstrate that TC degradation is an integrative contribution of both non-radical (1O2) and free radical (O2−, SO4−, and OH) pathways. Furthermore, Fe3O4@JDC also exhibits superior reusability (81.1 % degradation efficiency after five cycles) and magnetic separation ability.

RSM process optimization of biodiesel production from rapeseed oil and waste corn oil in the presence of green and novel catalyst

In the scenario of global warming and pollution, the green synthesis and use of biodiesel has acquired utmost priority. Due to several limitations of homogeneous catalysis, organobase immobilized heterogeneous catalyzed production of biodiesel has come out as a favored route. The present report demonstrates the design and synthesis of Peganum harmala spice seed extract modified GO-CuFe2O4 (SSE@GO-CuFe2O4) nanocomposite as an organobase functionalized high surface area magnetic nanocatalyst. Pistachio leaves were used in the green reduction of precursor salts to synthesize CuFe2O4 NPs. The as-synthesized nanomaterial was characterized physicochemically by Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive X-Ray analysis (EDX), elemental mapping, transmission electron microscopy (TEM), X-Ray diffraction (XRD), thermogravimetric analysis (TGA) and vibrating sample magnetometer techniques (VSM). Subsequently, the catalyst was explored in the efficient synthesis of biodiesels by trans-esterification of two substrates, the rapeseed oil and waste corn oil. The optimum conditions for biodiesel production were determined through response surface methodology based on Box–Behnken design including the study of calibration curves and 3D contour plots. Easy separation and workup, use of green medium, excellent reused for several times and short reaction time are outstanding benefits of this study.

Novel photocatalyst system to deep desulfurization of petroleum model and gas condensate by Box–Behnken design

In this research, cobalt (Co)/molybdenum (Mo) and nickel (Ni) doped with titanium dioxide (TiO2) were loaded onto multi-walled carbon nanotubes (MWCNTs). Then, the magnetization catalyst, iron oxide (Fe3O4), was loaded on them, which was used for the deep desulfurization of dibenzothiophene (DBT). These catalysts were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, differential reflectance spectroscopy, and Brunauer–Emmett–Teller, Barrett–Joyner–Halenda, and vibrating sample magnetometer techniques. The photocatalytic activity of these catalysts was experienced under visible light using DBT. The response surface methodology based on the Box–Behnken design was used to evaluate parameters, including catalyst dosage (g), time (min), and concentration of DBT (mg L−1). The highest degradation efficiency under optimal conditions for CoMoNi/TiO2/MWCNTs/Fe3O4 catalysts with a catalyst dosage of 0.3 g, a time of 180 min, and a concentration of 50 mg L−1 was 99.99%. Optimum conditions were studied for desulfurization of the gas condensate. The highest desulfurization efficiency (90.33%) was obtained by the CoMoNi/TiO2/MWCNTs/Fe3O4 catalyst.

Dielectric properties and magnetic behavior OF Gd3+ substituted M-type SrFe12O19 nanoferrites by auto combustion method using urea and citric acid mixtures as a dual fuel

Nanosized M-type hexaferrites Sr(1-x)GdxFe12O19 (x ​= ​0.00; 0.01<x ​< ​0.09; insteps of 0.02) have been synthesized by auto combustion method using urea and citric acid mixtures. Influences of Gd3+ ions substitution on structural, electrical and magnetic properties of Sr1-xGdxFe12O19 nanoferrites were investigated by XRD, FTIR, FESEM, LCR meter and VSM techniques. The PXRD studies confirmed the formation of single phase lattice whereas as the sample with x ​= ​0.09 exhibits about 5% of secondary phase. It was found that the lattice parameter increased with increasing in Gd3+ ion content. FTIR spectra have shown two absorption bands. The dielectric parameters were described based on the Maxwell–Wagner's two layer model. It is observed that the dielectric constant (ε′), the loss tangent (tanδ), decrease whereas the AC conductivity (σac) increases with increasing applied field frequency. Moreover, the vibrating sample magnetometer (VSM) analysis confirmed that M-SrHF's are hard magnetic in behavior. It was observed that the values of saturation magnetization (MS), remanence magnetization (Mr), coercivity (HC) and magnetic parameters of strontium ferrites decrease with the increase of the dopant Gd3+ in strontium ferrites. In addition, Gd3+ substituted SrFe12O19 are most useful for magnetic recording media and electro-magnetic devices.

Adsorption of tetracycline using CuCoFe2O4@Chitosan as a new and green magnetic nanohybrid adsorbent from aqueous solutions: Isotherm, kinetic and thermodynamic study

Utilizing a new microwave-assisted method, CuCoFe 2 O 4 @Chitosan (Ch) was synthesized as a very strong, magnetically separable nano-adsorbent. The magnetic nanohybrid adsorbent was characterized by FESEM (Field emission scanning electron microscopy ) , EDS (energy dispersive X-ray), Mapping & Linescan, BET (Brunauer-Emmett-Teller), FTIR (Fourier-transform infrared spectroscopy), XRD (X-ray diffraction analysis), TGA (Thermogravimetric analysis), and VSM (Vibrating Sample Magnetometer) techniques. Then, the adsorption process of Tetracycline (TC) was investigated. The highest percentage of pollutant adsorption on the synthetic and real samples was recorded at an initial concentration of 5 mg/L, pH 3.5, contact time of 20 min, the dose of 0.4 g/L, and temperature of 25 °C, 93.07 %, and 67%, respectively. The TC adsorption process via the synthesized magnetic nanocomposite was consistent with the Freundlich isotherm model (R 2 = 0.992) and pseudo -second-order kinetic (K 2 = 0.267). The outcomes of thermodynamic analyses, which included entropy changes (ΔS = 10.122 J/mol.k), enthalpy changes (ΔH = −1.975 kJ/mol), and the Gibbs negative free energy (ΔG = −4.992 kJ/mol), revealed that the adsorption process was spontaneous, favorable, and exothermic. The good magnetic properties allow easy separation after the adsorption operation. Finally, the efficiency of the nano-adsorbent in the removal process was 82.16% after four adsorption–desorption cycles. Some advantages of this research are a fast and green method for synthesis of adsorbent, fast kinetic, and magnetic properties to easy separation.

Magnetic, Optical Properties of Magnetite Nanoparticle Synthesized in Different Parameters

There are many methods for synthesizing magnetite nanoparticles. Most methods take a long time, and the result is undesirable. In this paper a green method was used to synthesize nanoparticles because it takes a short time and is both straightforward and eco-friendly. It is done by adding : =1:2 molar ratio solution with different amounts of extract and different amounts of NaOH solution for 20 min at different temperatures, in hotplate stirrers, to control their relative size. UV-Vis spectroscopy, vibrating sample magnetometer technique (VSM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) were used to characterize the magnetite nanoparticles. The result confirms that the changes in amounts of NaOH and extract led to a change in the pH of a solution and that the increase in amounts of the extract caused the low addition of NaOH. These changes influenced the process of synthesis and characterization. The Uv-vis analysis confirms that the surface plasmon resonance had a highly visible brad peak in the 290–460 nm range, as well as a peak shift to shorter wavelengths (blue shift) with a pH change and a peak shift to longer wavelengths (red shift) with a temperature change. TEM imaging confirms that all the synthesized had a spherical shape with size changed according to a parameter change of within 40–9 nm. Magnetic analysis showed the magnetite nanoparticles synthesized have smaller sizes and are superparamagnetic with the influence of particle size on the magnetic properties, including Hc, Ms, and Mr.

Integrated ultrasound-assisted magnetic solid-phase extraction for efficient determination and pre-concentration of polycyclic aromatic hydrocarbons from high-consumption soft drinks and non-alcoholic beers in Iran.

In the present research, an ultrasound-assisted magnetic solid-phase extraction coupled with a gas chromatography-mass spectrometry hybrid system was developed for the extraction/determination of trace amounts of polycyclic aromatic hydrocarbons in high-consumption soft drinks and non-alcoholic beers in Iran using magnetite graphene oxide adsorbent. The magnetite graphene oxide was characterized by scanning electron microscope, transmission electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, and vibrating-sample magnetometer techniques. The highest extraction recovery (73.05%-95.56%) and enrichment factor (90.65-106.38) were obtained at adsorbent mass: 10mg, adsorption time: 30min, salt addition: sodium chloride 10% w/v, desorption time: 20min, eluent type: hexane: acetone (1:1, v/v), and desorption solvent volumes: 200 μl. Under optimum conditions, the linearity range for polycyclic aromatic hydrocarbons determination was 0.2-200ng/mlwith a coefficient of determination>0.993, the limit of detection=0.09-0.21ng/ml, the limit of quantitation=0.3-0.7ng/ml, and relative standard deviation<8.1%, respectively. Relative recoveries in spiked real samples ranged from 94.67 to 109.45% with a standard deviation<6.05%. The proposed method is effective, sensitive, and reusable and it is promising for the analysis of polycyclic aromatic hydrocarbons residues in environmental samples.