Antimicrobial activity of metal-substituted cobalt ferrite nanoparticles synthesized by sol–gel technique

Therapeutic and diagnostic potential of nanomaterials for enhanced biomedical applications.

Synthesis and characterization of metals-substituted cobalt ferrite [Mx Co(1-x) Fe2O4; (M = Zn, Cu and Mn; x = 0 and 0.5)] nanoparticles as antimicrobial agents and sensors for Anagrelide determination in biological samples

Antibacterial, antibiofilm, and photocatalytic activities of metals-substituted spinel cobalt ferrite nanoparticles.

Biomolecules-mediated synthesis of selenium nanoparticles using Aspergillus oryzae fermented Lupin extract and gamma radiation for hindering the growth of some multidrug-resistant bacteria and pathogenic fungi.

The synthesis and characterization of silver nanoparticles (AgNPs) using natural pigments from plants as reducing agents is presented in this study. The natural pigments were extracted from Alfalfa leaves. The reduction reaction was investigated by UV–Vis and FTIR analyses. The synthesized AgNPs were characterized by UV–Vis, XRD, TEM, and DLS. UV–Vis analysis revealed that AgNPs were produced with a persistent plasmonic absorption peak at about 418 nm accompanied by consumption of pigments. The reduction is suggested to occur, mainly, by chlorophyll a and carotenes. Characterization revealed pure synthesized AgNPs with an average particle size of 25 nm. In an interesting novel experiment, the progress of reduction reaction was traced at the interface between reacting phases under UV illumination making use of fluorescence of both chlorophylls and formed Ag nano-clusters (AgNCs). The enrollment of chlorophylls in reduction was suggested depending on FTIR and fluorescence analyses. The synthesized AgNPs possessed a superior antimicrobial activity towards Staphylococcus aureus ATCC 29213; 24.0 mm ZOI, followed by Escherichia coli ATCC 25922; 17.0 mm ZOI. In addition, AgNPs were a strong antifungal agent against Candida albicans ATCC 10231; 26.0 mm ZOI.

Synthesis of silver nanoparticles using natural pigments extracted from Alfalfa leaves and its use for antimicrobial activity

Cerium is a rare earth element that has been widely proposed for the corrosion protection of aluminium alloys (AA). Both cerium salts, Ce3+ and Ce4+, have been used in combination with other compounds to offer synergistic inhibition, however, the inhibitive corrosion mechanism when using Ce4+ with organic compounds is still not clear. In this study, the synergistic inhibition effect of Ce4+ and melamine (M) on the corrosion of aluminium alloy 2024 (AA2024) in 3.5% NaCl solution was investigated. Potentiodynamic Polarization (PDP) and Electrochemical Impedance Spectroscopy (EIS) techniques were used to study the synergistic effect of different Ce4+/M ratios on the corrosion behaviour of AA2024. The PDP study showed that a combination of 50% Ce4+ and 50% M leads to the lowest corrosion rates, both acting as cathodic inhibitors. Both PDP and EIS results indicated that M or Ce4+ in isolation did not offer effective corrosion protection, while the combination of M and Ce4+ significantly enhances the corrosion protection with a synergism parameter equal to 3.5. SEM and EDX observations confirm the findings from the electrochemical techniques. XPS was used to investigate the mechanism of protection, revealing that the reduction of Ce4+ to Ce3+ occurs during protection of AA2024. A new mechanism of corrosion synergistic inhibition by Ce4+ and organic compounds is postulated where the role of the organic compounds is to enhance the reduction of Ce4+.

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Corrosion protection mechanism of Ce4+/organic inhibitor for AA2024 in 3.5% NaCl

Metal–organic frameworks (MOFs) have expanded into a burgeoning topic in materials science and engineering. Their success mostly stems from the versatility of their structure that can be diversely designed by precise control over the assembly. We conduct a critical review on the design and synthesis of MIL-101 MOFs, assessing the viability and applications of their diversified structures. Previous reviews are limited to the MIL-101(Cr). On the contrary, this study presents the synthesis strategies, the merits, and the limitations of the different MIL-101 metal analogues, including Fe, Al, V, Ti, Sc, and Mn. Furthermore, we review the literature on the multivariate type of MIL-101 (MTV-MIL-101), whereby pairwise combinations of metals are involved in the framework. We discuss how the synthesis parameters such as temperature, medium pH, and ratios of precursors intimately influence the final product characteristics. This study moreover presents the effects of changes in these parameters on the final framework structure. For instance, other polymorphs like MIL-88, MIL-53, MOF-235, MIL-47, and MIL-67 were detected in the final product. Finally, the recent applications of MIL-101 in adsorption, catalysis, photocatalysis, membrane preparation, sensor design, and drug delivery are presented and discussed.

Revisiting the MIL-101 metal–organic framework: design, synthesis, modifications, advances, and recent applications

Extract of Corchorus olitorius stems (ECS) was used as a green inhibitor for the inhibition of mild steel corrosion in 0.5 M H2SO4 solution. GC/MS was used for both qualitative and quantitative analysis of the extract. The corrosion performance of the extract was evaluated using electrochemical impedance spectroscopy, potentiodynamic polarization and weight loss. The results showed that ECS is a mixed-type inhibitor which reduces both anodic and cathodic reactions and the inhibition efficiency was reached up to 93%. Adsorption isotherm data was recorded at different temperatures and analyzed by selected adsorption isotherm models to reveal characteristics of inhibition. Thermodynamic calculations showed that the inhibition efficiency increases with increasing inhibitor concentration, and decreases with increasing temperature. Adsorption of ECS on the mild steel surface was found to be spontaneous and exothermic. Adsorption is suggested to be physisorption according to El-Awady isotherm model. Also, the scanning electron microscopy (SEM) was used to investigate the surface morphology to confirm the corrosion results.

https://iopscience.iop.org/article/10.1088/2053-1591/aa664a/pdf

Green corrosion inhibition of mild steel to aqueous sulfuric acid by the extract of Corchorus olitorius stems

We present the synthesis of a new cerium(III)–melamine coordination polymer (CMCP) by a mixed-solvothermal method and its characterization Characterization techniques included Raman, Fourier Transformation Infra-Red (FTIR), X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM), in which the change in the electronic environment and the crystallinity were tracked The characterization results confirm the coordination of cerium(III) with melamine through –NH2 groups, instead of the N atoms of the triazine ring, for which we propose a mechanism of interaction In addition, Biovia Materials Studio package was applied to determine and investigate the molecular structure of the CMCP All simulations were done using COMPASS force-field theory and atom-based method for summation of electrostatic and van de Waals forces The application of the CMCP for the corrosion inhibition of AA2024 in 35% NaCl solution was tested using the potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques The results point out that the presence of cerium as cerium(III) in the CMCP structure plays the fundamental role of inhibition, whereby the inhibition mechanism occurs by cathodic oxidation of Ce(III) to Ce(IV) and cyclic reduction of Ce(IV) to Ce(III) by melamine part of CMCP

/pdf/synthesis-of-a-novel-ce-iii-melamine-coordination-polymer-2duki6okr4.pdf

Mahmoud Y. Zorainy

Papers

Synthesis of silver nanoparticles using natural pigments extracted from Alfalfa leaves and its use for antimicrobial activity

Corrosion protection mechanism of Ce4+/organic inhibitor for AA2024 in 3.5% NaCl

Revisiting the MIL-101 metal–organic framework: design, synthesis, modifications, advances, and recent applications

Green corrosion inhibition of mild steel to aqueous sulfuric acid by the extract of Corchorus olitorius stems

Synthesis of a novel Ce(iii)/melamine coordination polymer and its application for corrosion protection of AA2024 in NaCl solution