This study reports the photocatalytic degradation of Methylene Blue (MB) dye (a class of dyestuffs that are resistant to biodegradation) under the influence of UV-light irradiation. Antibacterial and ...antibiofilm activities of ferrite nanoparticles (FO NPs) were examined against some pathogenic bacteria isolated from the medical operating room surfaces. In the same context, metals-substituted spinel cobalt ferrite nanoparticles with nominal composition MxCo1-xFe2O4 NPs; (M = Zn, Cu, Mn; x = 0.0, 0.25, 0.5 and 0.75) were synthesized by citrate sol-gel method. Also, the structures of the synthesized FO NPs were characterized by X-ray diffraction, and Williamson-Hall (WH) method was used to determine the crystallite size. The estimated specific surface area is found in the range from 37.99 to 107.05 m2/g, between the synthesized ferrites, Zn0.5Co0.5Fe2O4 NPs have average pore radius 1.84 nm and the pore volume was 0.136 ml/g. SEM images revealed that, the synthesized FO NPs have an unique pores and uniformly distribution, while EDX spectra shows the elemental composition for the synthesized FO NPs. The elastic properties of FO NPs have been estimated using FTIR data, whereas (M − H) hysteresis loops revealed that, by replacing cobalt ions with Zn, Cu, and Mn ions the magnetic behaviour changed from ferromagnetic to paramagnetic. Results obtained from the photocatalysis indicated that Mn0.75Co0.25Fe2O4 NPs (30.0 mg) were a promising photocatalyst achieving 96.0% removal of MB after 100 min of UV-light exposure in the alkaline solution. Antibacterial results showed that the most effective combination was Zn0.75Co0.25Fe2O4 NPs (20.0 ppm) displaying activity against Staphylococcus aureus, Enterococcus columbae, and Aerococcus viridians by 15.0, 13.0, and 12.0 mm ZOI, respectively. Additionally, Zn0.75Co0.25Fe2O4 NPs were active as antibiofilm factors producing activity by 63.7, 57.9, and 45.5% towards S. aureus, A. viridians, and E. columbae, respectively. Accordingly, Zn0.75Co0.25Fe2O4 and Mn0.75Co0.25Fe2O4 NPs can be utilized in industrial, biological and medical applications.
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•Citrate sol-gel mediates synthesis of metals-substituted spinel CFO NPs.•Morphological, elemental, crystal, and magnetic characterization.•Antibacterial and antibiofilm evaluation.•Photocatalytic degradation of MB estimation.•Promising nano-material for industrial, environmental, and biomedical applications.
Abstract
Two ferrite series were synthesized. One series has nanosize samples that have been prepared by the co-precipitation method, and the second series has the corresponding bulk samples that ...have been sintered at 1000 °C for 6 h. X-ray diffraction has been used to estimate the cubic spinel structure of both series. The crystallite size, theoretical density, and porosity of the nanomaterials are larger than those of the bulk materials. HRTEM analysis demonstrated the aggregation of nanoscale samples, including an average particle size of 9–22.5 nm. However, bulk specimens have a limited surface area. The agglomeration of the nanoparticles was seen in TEM images, in which the mean particle size was within the limit of the crystallite size (R) result and ranged from 14 to 20 nm. The appearance of the spinel phase in the samples was validated through Raman spectroscopy. Different cation occupation ratios in either tetrahedral or octahedral sites have been identified to be associated with an observable systematic shift and asymmetric flattening in Raman spectra with a variation in Cr
3+
concentration. The optical characterization was performed using the UV/Vis methodology, and the results reveal that the absorption cutoff frequency declines as the chromium content rises. It was also estimated that the optical bandgap averaged 3.6 eV for nanosamples and 4.6 eV for overall bulk materials. The highest photoluminescence emission was seen at wavelengths between λ
em
= 415 and 460 nm. The photoluminescence emission peaks of both bulk and nanoscale materials were red-shifted. These results accurately reflect the corresponding energy gap values for almost the same ranges. Sintering leads to a rise in photoluminescence.
Nanocrystalline spinel ferrite nanoparticles MxCo(1−x)Fe2O4;(M = Zn,Cu,Mn;x = 0 and 0.5) like: Cobalt ferrite (CFO), Zinc Cobalt ferrite (ZCFO), Copper Cobalt ferrite (CCFO), and Manganese Cobalt ...ferrite (MCFO) modified carbon paste electrodes (CPE) were synthesized via sol–gel technique utilizing citric acid and ethylene glycol as a polymerization agent. The synthesized ferrite NPs were used as bi-functional smart biosensor, not only used to determine the drug Anagrelide-HCl (ANDH) in urine and serum samples, but also possesses antimicrobial potential against some pathogenic microbes, founded in the biological samples. The synthesized ferrite NPs were confirmed by XRD, FTIR spectroscopy, SEM, EDX, and elemental mapping images. Antimicrobial activities of ferrite NPs against selected urinary tract infected microbes were investigated. From XRD data and FTIR spectroscopy it is found that the average crystallite size is lies in the range 12.86 to 33.92 ± 1.5 nm, also the bond lengths RA and RB increase from 1.8986 to 1.9145 Å and from 2.0434 to 2.0606 Å respectively and Debye temperature θD lies in the range of 681.52–708.87 K. Our study describes the improvement of a screen-printed sensor, modified with ferrite NPs materials for rapid, sensitive and cost-effective quantification of ANDH present in the real samples such as blood serum samples, urine and in the pharmaceutical formulations. The results obtained postulate a linear regression between the ANDH charge density of peak current and its concentration in the range from (0.64–8.18 μg/ml) with DL 0.31 μg/ml and QL 0.94 μg/ml. Antimicrobial results indicated that ZCFO NPs were a novel antibacterial agent against Klebsiella pneumoniae (28.0 mm ZOI), and multidrug-resistant bacteria Enterococcus faecalis (27.0 mm ZOI). Additionally, ZCFO NPs were active against Candida albicans (18.0 mm ZOI) seems to be a smart antifungal agent. Therefore, ZCFO NPs can be used as applicant resources for industrial, medical, and biological applications.
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•Synthesis and validation of spinel ferrite NPs using citrate sol-gel technique.•The theoretical values of lattice constant for ferrite NPs are approximated to experimentally lattice parameter values.•The Debye temperature for the ferrite NPs composition lies in the range of 681.52 – 708.87 K.•ZCFO NPs possessed a novel antimicrobial activity against selected MDR pathogens.•Improvement of a novel ZCFO NPs screen-printed sensors for rapid, sensitive and cost-effective ANDH quantification.
Precise tailoring of nanostructured cobalt ferrite paves the way to design and develop devices for stress and noncontact torque sensors. Herein, Mn
2+
ions are inserted into cobalt ferrite with ...different ratios using a facile sol–gel method. The as-synthesized ferrites are characterized via energy dispersive X-ray (EDX), Fourier transforms infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), high resolution transmission electron microscope (HR-TEM), thermogravimetric analysis (TGA), electrochemical impedance spectroscopy (EIS), and vibrating sample magnetometer (VSM). EDX analyses affirm the stoichiometry of the synthesized samples with the intended ratios. The FTIR and XRD prove the presence of a single-phase cubic spinel structure for all as-synthesized samples. The dislocation, the inter-chain distance and the distortion parameter values decrease with increasing Mn
2+
content, which outweigh the improvement of the crystal structure of the doped CFO samples. SEM micrographs illustrate that the incorporation of Mn
2+
significantly soars the porosity of the samples. TEM images reveal that the samples comprise particles in the nanometer range with spherical shape and porous nature. Thermal analyses show that the weight loss is dependent on Mn
2+
content in the sample. For instance, at
x
= 0, a slight variation in the weight loss estimated by 8% is observed while at
x
= 0.25 the weight loss has reached up to 40%. The dielectric losses (8 × 10
5
) of Co
0.5
Mn
0.5
Fe
2
O
4
is enough to meet the demands of microwave applications. Finally, a reduction in the magnetization of the pure CFO from 68.419 emu g
−1
to 50.307 emu g
−1
is achieved at
x
= 0.25.
Herein, manganese substituted cobalt ferrites were synthesized using a facile sol–gel method. The Rietveld refinements of Co
1-x
Mn
x
Fe
2
O
4
have studied. SEM images have indicated that the surface of the as-synthesized NPs has some porous shapes. EDX analyses have affirmed the stoichiometry of the samples. The TEM image reveals that particles are in the nanometer range. Thermal analyses show that the weight loss is dependent on Mn
2+
content in the sample. The dielectric losses (8 × 10
5
) of Co
0.5
Mn
0.5
Fe
2
O
4
is enough to meet the demands of microwave applications. The hysteresis loops reveal that the magnetic behavior of the CFO NPs is significantly influenced by Mn
2+
ions substitution.
Highlights
Mn
2
+ is successfully incorporated into cobalt ferrite (CoFe
2
O
4
) via sol–gel method.
XRD and Williamson-Hall analyses reveal that all samples comprise nanoparticles.
SEM micrographs show that the samples’ porosity soars with increasing Mn
2+
content.
TEM images reveal that the samples consist of spherical nanoparticle porous nature.
The sample of the highest content of Mn
2+
has the lowest Gibbs energy.
CaFeO3-δ perovskite nanomaterial has been synthesized by sol-gel method. Rietveld analysis of the X-Ray diffraction (XRD) data of the CaFeO3-δ sample revealed orthorhombic perovskite structure (space ...group pcmn). Field emission scanning electron microscope (FE-SEM) of the CaFeO3-δ sample showed the agglomerations of various particles. Mössbauer measurement of the CaFeO3-δ sample showed that the value of δ is 0.262 and Fe oxidation states are Fe3+ in octahedral and Fe4+ in tetrahedral coordination. X-ray photoelectron spectroscopy (XPS) revealed that the presence of Fe3+, Fe4+ ions, and oxygen vacancies at the surface of the CaFeO3-δ sample. Thermogravimetry analysis (TG) and differential scanning calorimetric (DSC) of the CaFeO3-δ sample revealed the presence of phase transitions. The magnetic properties of the CaFeO3-δ sample exhibit mainly antiferromagnetic state as confirmed by Mössbauer measurement. Based on the obtained results, the presence of oxygen vacancies and mixed oxidation states of iron (Fe3+ and Fe4+) makes the CaFeO3-δ sample useful for industrial applications.
•CaFeO3-δ perovskite nanomaterial has been synthesized by sol-gel method.•Mössbauer results revealed that the oxygen vacancy δ is 0.262.•Mössbauer results revealed that the Fe oxidation states are Fe3+ in octahedral and Fe4+ in tetrahedral coordination.•XPS results revealed that the presence of Fe3+, Fe4+ ions, and oxygen vacancies at the surface of the CaFeO3-δ sample.
La1-xAgxMnO3±δ (where x = 0.00, 0.04 and 0.08) perovskite samples were prepared by the co-precipitation method as electrode materials for supercapacitors. The characterizations of the prepared ...samples were performed using X-ray diffraction (XRD), high resolution transmission electron microscopic (HRTEM), dynamic light scattering (DLS), X-ray photoelectron spectroscopy (XPS), the Brunauer-Emmett-Teller (BET) surface area analysis and vibrating sample magnetometer (VSM). The structural characterizations of the prepared samples reveal that the samples are crystallized in rhombohedral perovskite crystal structure with space group R3c. The electrochemical properties were performed using cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) and electrochemical impedance spectroscopy (EIS). The present results show that Ag doped LaMnO3±δ can be used as a promising material in supercapacitor electrodes.
In this work, synthesis and characterization of SrFeO
3-δ
nanoparticles as antimicrobial agent are presented. Structural characterization of SrFeO
3-δ
sample shows that it has a cubic (Pm3m) phase ...with minor tetragonal phase. The morphology of the SrFeO
3-δ
nanoparticles sample was characterized by a field emission scanning electron microscope (FE-SEM) and high resolution transmission electron microscopy (HRTEM). Mössbauer spectroscopy and X-ray photoelectron spectroscopy (XPS) results showed that the iron exists in oxidation states Fe
3+
, Fe
3.5+
, and Fe
4+
. The SrFeO
3-δ
nanoparticles sample exhibits energy band gap (
E
g
= 1.75 eV) which lies in the Visible region. Thermal and magnetic studies provide an evidence for ferroelectricity and antiferromagnetic with small amount of ferromagnetic in SrFeO
3-δ
nanoparticles sample, respectively. SrFeO
3-δ
nanoparticles sample showing powerful activity to fight both of tested Gram-positive, Gram-negative bacteria, and fungi strains. The antimicrobial activity as well as the minimal inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of the SrFeO
3-δ
nanoparticles sample have been investigated.
Highlights
Perovskite sample was synthesized by a sol-gel method.
Mössbauer spectroscopy and XPS results showed that the iron existing in different states.
MBC studies of SrFeO
3-δ
sample indicate promising antimicrobial effectiveness.
A transparent composite sample containing BaTiO
3
was synthesized by using the melting quenching method. The presence of a glassy phase in this composite sample was detected through XRD analysis, and ...this was further confirmed by DSC study. TEM and SAED analyses provided evidence that the BaTiO
3
nanoparticles/clusters are embedded within the borate glass matrix, establishing the composite nature of this sample. FTIR spectrum of the present sample revealed that the glass matrix is composed of two structural groups (BO
3
with NBO’s, and BO
4
), along with the distinct groups for BaTiO
3
. XPS spectra of the present composite sample indicated the presence of more than one type of boron, barium, titanium and oxygen. DSC and dielectric studies of the present composite sample revealed the presence of the phase transition temperature (T
c
). Dielectric constant (ɛ
r
) and dielectric loss (tan δ) curves of the present composite sample displayed an anomaly peak in the vicinity of T
C
. The optical transmission spectrum of the present composite sample exhibit two transmission bands of Ti
3+
(3d
1
) ions in tetragonal distorted sites. At room temperature, the present transparent composite sample exhibited double hysteresis loops for BaTiO
3
at low electric fields. The results obtained can be used for the development of lead-free ferroelectric material.
This work reports the detailed structural characterization of Zn
2+
ion-substituted cobalt ferrite nanoparticles (CFO NPs; Co
1−x
Zn
x
Fe
2
O
4
; x = 0.00, 0.25, 0.50, and 0.75), prepared using a ...facile sol–gel method. It correlates structural changes with magnetic and dielectric properties. The as-synthesized samples were investigated by X-ray diffraction (XRD) analysis, BET surface area analyzer, energy-dispersive X-ray (EDX), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), Mössbauer spectroscopy, and impedance analyzer. The pristine sample (CFO) comprised of NPs with 25 nm size, which decreased up to 11 nm upon the formation of Zn
0.75
Co
0.25
Fe
2
O
4
. The N
2
adsorption–desorption isotherm of the prepared Zn
0.5
Co
0.5
Fe
2
O
4
sample confirmed the presence of a mesoporous structure. SEM images revealed that all prepared samples exhibited porous surface with honeycomb-like structures. The cationic distribution was described by Mössbauer spectra. The increment of Zn ions in the prepared samples resulted in sharp reduction of saturation magnetization and remanence values. The normal dielectric dispersion behavior was recorded and can be ascribed to the Maxwell–Wagner type polarization. Besides, the dielectric parameters varied by increasing Zn content in CFO NPs. This may be ascribed to O
2
vacancies and Fe
3+
ions in A- and B-sites. Dielectric studies revealed that, content of Zn ions beyond
x
= 0.25 was sufficient to reduce both dielectric constant and loss at low frequencies.
Glasses with the composition, (30−x)V2O5–xBaTiO3–70 TeO2 with x=5, 10 and 15 (in mol%) were prepared. The amorphous nature and glassy characteristics of the samples were established via X-ray powder ...diffraction (XRD) and differential scanning calorimetry (DSC) respectively. The nanocrystalline of BaTiO3 embedded in the network glass matrix at x=15mol% were established by DSC which is confirmed by infrared spectroscopy study. Properties such as density, molar volume, dielectric constant, dielectric loss and AC conductivity, as a function of frequency (120Hz–100kHz) and temperature (300–500K), have been investigated. The trends of these properties are attributed to changes in the glass network structure and presence of nanocrystalline of BaTiO3. The sample at x=15mol% exhibited dielectric anomaly and the Curie–Weiss law was found to be valid at a temperature above the transition temperature (Tc).
•Vanado-tellurite glasses containing BaTiO3 ranging from 5 to 15mol% were synthesized.•The sample at x=15mol% of contains nanocrystalline BaTiO3 embedded in the glass matrix.•The sample at x=15mol% exhibits dielectric anomaly.
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