Modified cellulose acetate antibacterial material was obtained by immobilizing Al/Ag nanoparticles on fabric fibres in water and subsequent hydrolysis of this nanoparticles under mild reaction ...condition. AlOOH/Ag self-assembled flower-shaped nanostructures consist of AlOOH nanoplates and Ag inclusions. The AlOOH nanosheets size is of 150–300 nm, thickness is 5–7 nm. The silver inclusions were from 5 to 30 nm in size. Flower-shaped AlOOH/Ag nanostructures change the charge of fibres and stabilize Ag nanoparticles against agglomeration. The positive charge of the modified fibres improves the bacteria adsorption due to electrostatic interaction. The antibacterial activity of the nanoparticles and modified material arise due to the slow Ag
+
migration into the medium from stabilized Ag nanoparticles. The nanoparticles and modified cellulose acetate sheets were characterized by transmission and scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction analysis, FTIR spectroscopy. The release of silver ions to the medium remains low for 70 h with AlOOH/Ag@CA reducing all the tested bacterial strains below the limit of detection (10
2
CFU/mL) within 3 h for
Escherichia coli
and 6 h for MRSA due to local effects of silver on adsorbed bacteria. The antibacterial activity of modified cellulose acetate fabric allows this method of modification to be exploited to produce materials for biomedical applications.
A novel route for the synthesis of boehmite nanospheres with a hollow core and the shell composed of highly crumpled AlOOH nanosheets by oxidizing Al nanopowder in pure water under mild processing ...conditions is described. The stepwise events of Al transformation into boehmite are followed by monitoring the pH in the reaction medium. A mechanism of formation of hollow AlOOH nanospheres with a well-defined shape and crystallinity is proposed which includes the hydration of the Al oxide passivation layer, local corrosion of metallic Al accompanied by hydrogen evolution, the rupture of the protective layer, the dissolution of Al from the particle interior and the deposition of AlOOH nanosheets on the outer surface. In contrast to previously reported methods of boehmite nanoparticle synthesis, the proposed method is simple, and environmentally friendly and allows the generation of hydrogen gas as a by-product. Due to their high surface area and high, slit-shaped nanoporosity, the synthesized AlOOH nanostructures hold promise for the development of more effective catalysts, adsorbents, vaccines and drug carriers.
Electric explosion of zinc and silver intertwined wires in an oxygen-containing atmosphere was used for the first time to produce ZnO–Ag bicomponent nanoparticles. Silver content was regulated by ...wire diameters. The nanoparticles were characterized by transmission electron spectroscopy, X-Ray diffraction. Optical properties of ZnO–Ag nanoparticles were studied by ultraviolet–visible spectroscopy. The phase state of nanoparticles in the range of high (12–35%) silver content has been established, which provides an increase in the photocatalytic activity in the visible spectral range. The Methylene blue degradation efficiency by ZnO-12Ag nanoparticles reached 90%, which was higher than that of ZnO nanoparticles produced by electric explosion of zinc wire. Composites had high antibacterial activity against
Escherichia coli
bacteria.
The creation of new nanomaterials with improved characteristics, as well as the development of new approaches to obtain such materials is an urgent task in science and technology. One of the ...promising directions in obtaining improved nanomaterials is the use of precursors in the form of multicomponent metal nanoparticles. Thermal oxidation of bimetallic Ti/Al nanoparticles obtained by electrical explosion of wires was investigated in this work. Ti/Al nanoparticles have been found to be completely oxidized with the formation of composite TiO
2
/Al
2
O
3
nanoparticles after calcination at 900 °C. The formation of TiO
2
phase with a rutile structure on heating to 500 °C, and the formation of TiO
2
phases with a rutile and anatase structure, as well as α-Al
2
O
3
on heating to 700 °C have been established, in addition to the residue of unoxidized metals. Complete oxidation of Ti/Al nanoparticles occurs when heated to 900 °C. The photochemical activity of TiO
2
/Al
2
O
3
composite nanoparticles obtained at 900 °C was studied. The degradation of methyl orange dye reached 55% under UV irradiation for 120 min.
The AlOOH/Cu modified cellulose acetate fibres were prepared by a facile one-step method. First, the cellulose acetate fibres were treated in an aqueous suspension with the bimetallic Al/Cu ...nanoparticles, followed by their oxidation. Copper and copper intermetallides do not react with water, while the aluminum does with boehmite formation. During this process AlOOH/Cu particles consisting of boehmite nanosheets self-assembled into flower-like agglomerates, and copper-rich fragments with size of 2 nm were formed. These inclusions could be spread uniformly through the whole volume of nanosheets or form a solid spherical copper-rich core in the center of AlOOH/Cu particles. The AlOOH nanosheets provide an adhesive attachment of the particles on the surface of the cellulose acetate fibres, and the slow migration of copper ions through the shell into the surrounding medium. The morphology, physical and chemical properties of the materials were characterized by transmission electron microscopy, scanning electron microscopy, X-ray diffraction, energy dispersive X-ray spectroscopy, adsorption of nitrogen (BET method), Fourier transform infrared spectroscopy and electrophoretic mobility (ζ-potential measurement). The antibacterial activity of the hybrid fibrous sorbent prepared against
Escherichia Coli
and
Staphylococcus Aureus
was studied. Reduction of the concentration viable bacteria reached 100 % after exposure of the bacteria for 1 h to the hybrid fibrous absorbent.
The development of new materials with antibacterial properties is a promising direction in the field of nanotechnology. In this work, ZnO–Ag nanoparticles with a silver content of 0.1–50 at % have ...been fabricated by the exploding wire method. ZnO–Ag nanoparticles absorb visible light and destroy the model dye Rhodamine B. The introduction of silver into nanoparticles has made it possible to shift the main absorption edge to 1.59–2.74 eV. The determined optimal content of silver in nanoparticles of 12 at % has ensured the degree of Rhodamine B decoloration by 85% within 60 min of exposure to visible light and has completely stopped the growth of
E. coli
bacteria at a concentration of 15.6 µg/mL. In addition, nanoparticles containing 12 at % silver have sterilized a sample of natural water contaminated with microorganisms. The results obtained offer an efficient method for the synthesis of antibacterial nanocomposites with heterojunctions employing a high-performance technique for producing nanoparticles, namely, the exploding wire method.
Therefore, researchers devote special attention to the search of new composite nanoparticles for biomedical applications. In this research CuO–ZnO composite nanoparticles was synthesized by ...electrical explosion of cooper and zinc wires in oxygen containing atmosphere. The atomic ratio of metals in the nanoparticles was regulated by varying the wire diameters. The as-synthesized nanoparticles were characterized by powder x-ray diffraction analysis, transmission electron microscopy, energy-dispersive x-ray spectroscopy techniques, sedimentation method, micro electrophoresis and adsorption of nitrogen (BET method). The particles are mostly spherical or close to spherical shape. In the x-ray diffraction patterns of the synthesized nanoparticles the main reflexes correspond to the phases of ZnO and CuO. Furthermore, antibacterial activity of ZnO–CuO nanoparticles against
Escherchia coli
(ATCC 25922) and MRSA (ATCC 43300) were studied, using agar diffusion test and micro dilution assay. Theses result showed synthesized CuO–ZnO nanoparticles have efficient antibacterial activity against gram positive and gram negative bacteria and exceed the antibacterial activity of ZnO and CuO nanoparticles.
The chemical compositions, structures, and electrokinetic potentials have been studied for silver-containing Janus-type ZnO/Ag nanoparticles, heterophase Cu/Ag nanoparticles with a uniform ...distribution of the components over a particle, and silver-decorated TiO
2
nanoparticles. The nanoparticles have been obtained by the simultaneous electric explosion of two wires. The influence of nanoparticle surface structure on the isoelectric point position and electrokinetic potential values has been analyzed. The effect of silver localization on the electrokinetic characteristics of nanoparticles has been investigated. These characteristics have been compared with those of mechanical mixtures having the same mass ratios of the components.
Bimetallic Al–Cu and Al–Ag nanoparticles were synthesized by electric explosion of wires in an argon atmosphere. The mass ratio of aluminum and the second metal (Me = Cu or Ag) was ~ 90 : 10 and was ...controlled by the diameter of the dispersed metal wires. Mesoporous AlOOH–Me nanocomposite was obtained by simple oxidation of Al–Me precursors with water at a temperature of 60°С. The kinetic regularities of the oxidation of Al–Me nanoparticles in dilute aqueous suspensions were studied. The effect of the second metal on the structure, morphology, and antibacterial activity of nanocomposites against methicillin-resistant
Staphylococcus aureus
(MRSA) bacteria was studied. It has been shown that the synthesized AlOOH–Me nanocomposites possess high antibacterial activity and are promising and highly efficient antimicrobial agents.
In the present work, we have synthesized for the first time zinc titanate nanoparticles by electrical explosion of titanium and zinc wires in an oxygen-containing atmosphere (argon–oxygen 20 vol.%). ...As-synthesized nanoparticles were characterized using transmission electron microscopy, x-ray diffraction analysis, and x-ray photoelectron spectroscopy. The particles have spherical shapes and an average particle size of 82 nm. The phase composition is presented by zinc titanate and a small amount of titanium oxide, which corresponds to the phase diagram of the TiO
2
–ZnO system. The photocatalytic activity of the synthesized nanoparticles studied in the decomposition reaction of model dye methylene blue was higher than that of titanium oxide nanoparticles obtained by electrical explosion of a titanium wire in an oxygen-containing atmosphere. In addition, the synthesized nanoparticles demonstrated high antibacterial activity against methicillin-resistant staphylococcus aureas (MRSA) bacteria.
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