Mn0.2Co0.8Fe2O4 and encapsulated Mn0.2Co0.8Fe2O4/SiO2 magnetic nanoparticles for efficient Pb2+ removal from aqueous solution

2019 ◽  
Vol 80 (2) ◽  
pp. 377-386
Author(s):  
Kamal R. Awad ◽  
M. M. S. Wahsh ◽  
Shaimaa T. El-Wakeel ◽  
Kingsley I. Ochiabuto ◽  
A. G. M. Othman ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Particle Size ◽  
Magnetic Nanoparticles ◽  
Spinel Ferrite ◽  
Sol Gel ◽  
Solution Ph ◽  
Transition Electron Microscopy ◽  
Auto Combustion ◽  
Langmuir Isotherm Model ◽  
Modified Stöber Method

Abstract Sol-gel auto-combustion technique was used to synthesize spinel ferrite nanoparticles of Mn0.2Co0.8Fe2O4 (MCF). Using the modified Stöber method, these magnetic nanoparticles were encapsulated with silica to form the core/shell Mn0.2Co0.8Fe2O4/SiO2 (MCFS). The phase composition, morphology, particle size, and saturation magnetization of the encapsulated nanoparticles were studied using X-ray diffraction (XRD), high resolution-transition electron microscopy (HR-TEM), and vibrating sample magnetometer (VSM). HR-TEM images indicated that particle size of the nanoparticles ranged from 15 to 40 nm, and VSM measurements showed that Ms of uncoated and coated samples were 65.668 emu/g and 61.950 emu/g and the Hc values were 2,151.9 Oe and 2,422.0 Oe, respectively. The effects of metal concentration, solution pH, contact time, and adsorbent dose of the synthesized nanoparticles on lead (Pb2+) ions removal from an aqueous solution were investigated. Based on Langmuir isotherm model, the results for peak adsorption capacity of the adsorbent under optimal conditions was 250.5 mg/g and 247 mg/g for MCF and MCFS, respectively. We concluded that Pb2+ adsorption occurred via a chemisorption mechanism based on the analysis of adsorption kinetics. The adsorbents displayed consistent adsorption efficiencies following three cycles of regeneration, indicating that these magnetic nanoparticles are promising candidates for wastewater purification.

Preparation of Magnesium-Based Cobalt-Ferrites (Co1−xMgxFe2O4) Nanoparticles by Sol–Gel Auto Combustion Method

2017 ◽  
Vol 17 (01n02) ◽  
pp. 1760012
Author(s):  
S. Gowreesan ◽  
A. Ruban Kumar
Keyword(s):  
Particle Size ◽  
Structural Parameters ◽  
Sol Gel ◽  
Average Particle Size ◽  
Combustion Method ◽  
Dielectric Behavior ◽  
Powder Xrd ◽  
Average Particle ◽  
Cobalt Ferrites ◽  
Auto Combustion

The scope of the present work is in enhancing the particle size, and dielectric properties of Mg-substituted Cobalt ferrites nanoparticles prepared by sol–gel auto combustion method. The different ratios of Mg-substituted Co Ferrites (Co[Formula: see text]MgxFe2O4([Formula: see text], 0.05, 0.10, 0.15, 0.20 and 0.30)) are calcinated at 850[Formula: see text]C. The synthesized nanoparticles were characterized by powder XRD, FTIR, FE-SEM, EDX techniques and dielectric behavior. The structural parameters were confirmed from powder XRD and the average particle size is obtained from 39 to 67 nm due to the substitution of Mg[Formula: see text] which was calculated by Debye Scherrer’s formula. FE-SEM showed the surface morphology of the different ratio of the sample. The dielectric loss has measured the frequency range of 50[Formula: see text]Hz–5[Formula: see text]MHz. From electrical modulus, conductivity relaxation and thermal activation of charge carriers has been discussed.

Effect of Annealing Temperature on Phase Transition of Nanoalumina Synthesized by Auto-Combustion Route

2016 ◽  
Vol 41 ◽  
pp. 74-86 ◽  
Author(s):  
Muhammad Adil ◽  
Hasnah Mohd Zaid ◽  
Kean Chuan Lee ◽  
Noor Rasyada Ahmad Latiff
Keyword(s):  
Phase Transition ◽  
Particle Size ◽  
Sol Gel ◽  
Thermo Gravimetric Analysis ◽  
Amorphous State ◽  
Specific Area ◽  
Combustion Method ◽  
Gravimetric Analysis ◽  
Crystalline Phases ◽  
Auto Combustion

Nanocrystalline Al2O3 powder has been successfully synthesized by a simple and fast sol-gel auto-combustion method. The transformation of crystalline phases of as-synthesized nano powders was investigated through X-ray diffraction in terms of their crystallinity and crystallite size. Subsequently, a detailed transmission electron microscopy (TEM) investigation, including specific area electron diffraction (SAED) analysis revealed the crystallographic alterations and morphological information even at lattice scale which co-include the XRD analysis. The results obtained allow to explain the evolution of an amorphous state into different crystalline phases with increased calcining temperature; and their relation to particle size. The particle size is found to be closely related to phase transition of Al2O3 from γ → δ → θ → κ →α. The existence of distinctive bonds and band energy were studied by employing Fourier-transform infrared spectroscopy (FTIR) and UV-visible spectroscopy, respectively. On the other hand, thermo gravimetric analysis (TGA) had also been performed to confirm the phase purity of nano powder.

Fabrication of chitosan-coated mixed spinel ferrite integrated with graphene oxide (GO) for magnetic extraction of viral RNA for potential detection of SARS-CoV-2

2021 ◽  
Author(s):  
Vijay Singh ◽  
Khalid Mujasam Batoo ◽  
Mahavir Singh
Keyword(s):  
Graphene Oxide ◽  
Magnetic Nanoparticles ◽  
Transmission Rate ◽  
Spinel Ferrite ◽  
Sol Gel ◽  
Rna Extraction ◽  
Magnetic Studies ◽  
Mixed Spinel ◽  
Diagnostic Approaches ◽  
Magnetic Extraction

Abstract Genetic variants of the COVID-19 causative virus have been arising and circulating globally. In many countries especially in developing ones with a huge population, vaccination has become one of the major challenges. SARS-CoV-2 variants’ fast transmission rate has upsurge the COVID cases, leading to more stress on health systems. In the current COVID-19 scenario, there is the requirement of more adequate diagnostic approaches to check the COVID-19 spread. Out of many diagnostic approaches, a magnetic nanoparticle-based reverse transcription-polymerase chain reaction could be nontrivial. The use of magnetic nanoparticles to separate nucleic acid of SARS-CoV-2 from the patient samples and applied for detection is an easy and more effective way for COVID-19 patient detection. Herein, the magnetic nanoparticles are synthesized using the sol-gel autocombustion methods and then, successfully coated with biopolymer (chitosan) using ultra-sonication. Chitosan-coated nanoparticles are successfully integrated into the graphene oxide sheets to introduce carboxyl groups. Crystallite size calculation, morphological and magnetic studies of synthesized magnetic nanoparticles, and multifunctional magnetic nanoparticles are done using XRD, SEM, TEM, and VSM respectively. Besides the potentiality of the fabricated nanocomposites in RNA extraction protocol is also discussed with schematic representation.

Structural and magnetic properties of Cr doped strontium spinel ferrite SrFe2O4 by sol-gel auto-combustion method

2018 ◽  
Vol 550 ◽  
pp. 90-95 ◽  
Author(s):  
Nazia Yasmin ◽  
Iqra Inam ◽  
Iftikhar Ahmed Malik ◽  
Maria Zahid ◽  
Muhammad Naeem Ashiq ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Spinel Ferrite ◽  
Sol Gel ◽  
Combustion Method ◽  
Auto Combustion ◽  
Structural And Magnetic Properties

scholarly journals (3-Aminopropyl) Triethoxysilane (APTES) Functionalized Magnetic Nanosilica Graphene Oxide (MGO) Nanocomposite for the Comparative Adsorption of the Heavy Metal (Pb(II), Cd(II) and Ni(II)) ions from Aqueous Solution

2021 ◽  
Author(s):  
C Donga ◽  
S Mishra ◽  
A Aziz ◽  
L Ndlovu ◽  
A Kuvarega ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Graphene Oxide ◽  
Metal Ion ◽  
Ion Concentration ◽  
Batch Adsorption ◽  
Solution Ph ◽  
Magnetic Graphene Oxide ◽  
Equilibrium Data ◽  
Langmuir Isotherm Model ◽  
Adsorption Equilibrium Data

Abstract (3-aminopropyl) triethoxysilane (APTES) modified magnetic graphene oxide was synthesized and applied in the adsorption of three heavy metals, Pb(II), Cd(II) and Ni(II) from aqueous solution. An approach to prepare magnetic GO was adopted by using (3-aminopropyl) triethoxysilane (APTES) as a functionalizing agent on magnetic nanosilica coupled with GO to form the Fe3O4@SiO2-NH2/GO nanocomposite. FT-IR, XRD, BET, UV, VSM, SAXS, SEM and TEM were used to characterize the synthesized nanoadsorbents. Batch adsorption studies were conducted to investigate the effect of solution pH, initial metal ion concentration, adsorbent dosage and contact time. The maximum equilibrium time was found to be 30 min for Pb(II), Cd(II) and 60 min for Ni(II). The kinetics studies showed that the adsorption of Pb(II), Cd(II) and Ni(II) onto Fe3O4@SiO2-NH2/GO followed the pseudo-second-order kinetics. All the adsorption equilibrium data were well fitted to Langmuir isotherm model and maximum monolayer adsorption capacity for Pb(II), Cd(II) and Ni(II) were 13.46, 18.58 and 13.52 mgg-1, respectively. The Fe3O4@SiO2-NH2/GO adsorbents were reused for at least 7 cycles without the leaching of mineral core, showing the enhanced stability and potential application of Fe3O4@SiO2-NH2/GO adsorbents in water/wastewater treatment.

scholarly journals Magnetocrystalline and Surface Anisotropy in CoFe2O4 Nanoparticles

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1288 ◽  
Author(s):  
Alexander Omelyanchik ◽  
María Salvador ◽  
Franco D’Orazio ◽  
Valentina Mameli ◽  
Carla Cannas ◽  
...  
Keyword(s):  
Particle Size ◽  
Magnetic Anisotropy ◽  
Annealing Temperature ◽  
Ac Susceptibility ◽  
Sol Gel ◽  
Combustion Method ◽  
Anisotropy Constant ◽  
Silica Matrix ◽  
Thermal Treatments ◽  
Auto Combustion

The effect of the annealing temperature Tann on the magnetic properties of cobalt ferrite nanoparticles embedded in an amorphous silica matrix (CoFe2O4/SiO2), synthesized by a sol-gel auto-combustion method, was investigated by magnetization and AC susceptibility measurements. For samples with 15% w/w nanoparticle concentration, the particle size increases from ~2.5 to ~7 nm, increasing Tann from 700 to 900 °C. The effective magnetic anisotropy constant (Keff) increases with decreasing Tann, due to the increase in the surface contribution. For a 5% w/w sample annealed at 900 °C, Keff is much larger (1.7 × 106 J/m3) than that of the 15% w/w sample (7.5 × 105 J/m3) annealed at 700 °C and showing comparable particle size. This indicates that the effect of the annealing temperature on the anisotropy is not only the control of the particle size but also on the core structure (i.e., cation distribution between the two spinel sublattices and degree of spin canting), strongly affecting the magnetocrystalline anisotropy. The results provide evidence that the magnetic anisotropy comes from a complex balance between core and surface contributions that can be controlled by thermal treatments.

Preparation and Magnetic Properties of Monodisperse Nanocomposite Hollow Spheres

2007 ◽  
Vol 998 ◽  
Author(s):  
Chun-Rong Lin ◽  
Cheng-Chien Wang ◽  
I-Han Chen
Keyword(s):  
Particle Size ◽  
Electron Microscope ◽  
Saturation Magnetization ◽  
Magnetic Measurements ◽  
Spinel Ferrite ◽  
Sol Gel ◽  
Hollow Spheres ◽  
Core Shell ◽  
Ferromagnetic Behavior ◽  
Mixed Gas

ABSTRACTWe present a simple process to prepare the hollow ceramic (CoFe2O4/SiO2) composite nanospheres and hollow alloy (Co33Fe67/SiO2) composite nanospheres. The hollow CoFe2O4/SiO2 composite nanospheres were prepared by calcining polymer/CoFe2O4/SiO2 core/shell composite spheres which were synthesized by the sol-gel method following the chemical co-precipitation. In a typical process, the monodisperse polymer poly(MMA-co-MAA) latex (450 nm) was used as a core template. To create hollow CoFe2O4/SiO2 spherical structures with various sizes of CoFe2O4 nanoparticles, the hybrid PMMA/CoFe2O4/SiO2 core-shell spheres were subsequently calcined in the temperature range from 450 to 900°C for 4h. On the other hand, the hollow Co33Fe67/SiO2 composite nanospheres were formed by reduction of hollow CoFe2O4/SiO2 nanospheres in a stream of H2/Ar mixed gas at 900°C for 8 hrs. X-ray diffraction pattern shows that the coated phase of the hollow CoFe2O4/SiO2 composite nanospheres has a cubic spinel ferrite structure. Based on the thermogravimetric analysis (TGA), we found that the content of CoFe2O4 is 73 wt% in the hollow CoFe2O4/SiO2 composite shell. The scanning electron microscope and transmission electron microscope photographs show that the hollow spheres are uniform. According to the line scanning EDX analysis of the cross section of hollow spheres, the SiO2 is not only coated on the surface of sphere but also distributed over the shell of hollow sphere. The thickness of shell of hollow spheres is about 40 nm. Magnetic measurements show that the saturation magnetization is clearly decreases as the magnetic particle size decreased. This phenomenon can be interpreted as the effect of surface spin canting when the particle size is reduced. As for the hollow alloy (Co33Fe67/SiO2) composite nanospheres, the magnetic phase has a body-centered cubic structure and an average crystallite size of 28.7 nm. This alloy nanospheres exhibit a ferromagnetic behavior with saturation magnetization of 170 emu/g, coercivity of 250 Oe, and Curie temperature of 968 °C. Due to metallic and ferromagnetic behavior of Co33Fe67 nanoparticles, these hollow spheres can be used as a lightweight electromagnetic wave absorber.

Effect of La3+ Substitution on the Structural and Magnetic Properties of Mn-Zn Ferrite Prepared by Sol-Gel Auto-Combustion Method

2018 ◽  
Vol 916 ◽  
pp. 91-95
Author(s):  
Beh Hoe Guan ◽  
Muhammad Hanif bin Zahari ◽  
Kean Chuan Lee
Keyword(s):  
Magnetic Properties ◽  
Rare Earth ◽  
Spinel Ferrite ◽  
Sol Gel ◽  
Combustion Method ◽  
Secondary Phases ◽  
Zn Ferrite ◽  
Auto Combustion ◽  
Structural And Magnetic Properties ◽  
The Rare Earth

Spinel ferrite with the chemical formula of Mn0.5Zn0.5LaxFe2-xO4(x= 0.02, 0.04, 0.06, 0.08, 0.10) were prepared by a sol-gel auto-combustion method. The effect of the rare-earth substitution on the microstructural properties of the synthesized powders were investigated through X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM), while for the magnetic properties, vibrating sample magnetometer (VSM) measurements were made. XRD patterns revealed characteristic peaks corresponding to spinel Mn-Zn ferrite structures with accompanying secondary phases, such as Fe2O3and LaFeO3. The initial addition of La3+into the spinel ferrite system resulted in an initial spike of the lattice parameter and crystallite size before proceeding to decrease as the rare-earth content continues to decrease. FESEM micrographs reveals agglomerated particles with considerable grain size distribution. The magnetic properties, especially the saturation magnetization,Ms, was found to decrease with each increase in La3+substitution. The research findings revealed the critical influence of the La3+substitution towards the overall structural and magnetic properties of the Mn-Zn ferrite samples.

Synthesis of Monodisperse Fe3O4 and MnFe2O4 Nanospheres by Using a Solvothermal Reduction Method

2011 ◽  
Vol 181-182 ◽  
pp. 393-396 ◽  
Author(s):  
Gui Hua Ren ◽  
Zhi Song Yu
Keyword(s):  
Reduction Method ◽  
Hydrothermal Reaction ◽  
Spinel Ferrite ◽  
Sol Gel ◽  
Decomposition Methods ◽  
Spinel Ferrites ◽  
Storage Devices ◽  
Auto Combustion ◽  
Potential Applications ◽  
Average Size

The spinel ferrites, MFe2O4(where M=Fe, Mn, Co, Ni, Zn, Mg, etc.) have attracted considerable interest during the last few decades due to their potential applications in high frequency transformers, filters, high density storage devices, and microwave applications. In the latest several years, many synthesis technologies such as sol-gel, auto-combustion, thermal decomposition methods and hydrothermal reaction have been developed to prepare spinel ferrite nanoparticles. In this paper, the spinel ferrites Fe3O4and MnFe2O4nanoparticles were synthesized by using a solvothermal reduction method. X-ray diffraction (XRD) and Raman analysis shows that all the peaks are close to the data for Fe3O4and MnFe2O4, indicating the prepared particles are single phase. The scan electronic microscopy (SEM) shows that the prepared Fe3O4and MnFe2O4are monodisperse nanospheres and with the average size of around 300nm.

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