Evgeny Kolesnikov

Synthesis of five metal based nanocomposite via ultrasonic high temperature spray pyrolysis with excellent antioxidant and antibacterial activity

A unique five metal (Zn, Cu, Ni, Fe, and Mg) based nanocomposite material was prepared via ultrasonication high temperature spray pyrolysis maintained at 1200 °C. The influence of different concentrations (0.001 M, 0.01 M, and 1 M) on size and crystalline phase were analyzed. The nanocomposite exhibited excellent antioxidant and antibacterial activity.

Nitrobacter sp. extract mediated biosynthesis of Ag2O NPs with excellent antioxidant and antibacterial potential for biomedical application

In this study, extracellular extract of plant growth promoting bacterium, Nitrobacter sp. is used for the bioconversion of AgNO3 (silver nitrate) into Ag2O (silver oxide nanoparticles). It is an easy, ecofriendly and single step method for Ag2O NPs synthesis. The bio-synthesized nanoparticles were characterized using different techniques. UV-Vis results showed the maximum absorbance around 450 nm. XRD result shows the particles to have faced centered cubic (fcc) crystalline nature. FTIR analysis reveals the functional groups that are involved in bioconversion such as C-N, N-H and C=O. Energy-dispersive X-ray spectroscopy (EDAX) spectrum confirms that the prepared nanoparticle is Ag2O NPs. Particle size distribution result reveals that the average particle size is around 40 nm. The synthesized Ag2O NPs found to be almost spherical in shape. Biosynthesized Ag2O NPs possess good antibacterial activity against selected Gram positive and Gram negative bacterial strains namely Salmonella typhimurium, Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae when compared to standard antibiotic. In addition, Ag2O NPs exhibits excellent free radical scavenging activity with respect to dosage. Thus, this study is a new approach to use soil bacterial extract for the production of Ag2O NPs for biomedical application.

The effects of liquid-phase oxidation of multiwall carbon nanotubes on their surface characteristics

The development of new sorbents based on nanostructured carbon materials recently became a perspective field of research. Main topic of current study is to investigate the effect of different regimes of multiwall carbon nanotubes (MWCNT) surface modification process on their structural characteristics. MWCNT samples were treated with nitric acid at high temperature. Structural properties were studied using low temperature nitrogen adsorption and acid-base back titration methods. The study showed that diluted nitric acid does not affect MWCNT structure. Concentrated nitric acid treatment leads to formation of 2.8 carboxylic groups per 1 nm2 of the sample surface.

Recent advances and future perspectives of nanosized zero- valent iron for extraction of heavy elements from metallurgical sludges

Advanced oxidation processes with nanosized zero-valent iron have presented great potential in wastewater treatment technology and now experience both increasing popularity and reliable technical improvements. Besides wastewater treatment, there is another promising application for an emerging technology of iron nanoparticles - as Fenton-like catalyst for extraction of valuable elements from poor and secondary raw materials such as metallurgical sludges. In present research, we carried out a set of experiments with emphasis on the physicochemical mechanisms and their relationship to the performance. In particular, we examined complex acidic - hydrogen peroxide leaching of zinc from blast furnace sludge with nanosized zero-valent iron as Fenton-like catalyst. Results of the experiments showed promising potential for subsequent application in extraction of heavy and rare-earth elements.