Nanoparticles In Technologies Research Articles

Effect of Trifluralin, Zero-Valent Iron and Magnetite Nanoparticles on Growth of Micromycetes

Abstract Nowadays many reports confirmed the effect of different nanoparticles (NPs) on the growth and secondary metabolite production in various microorganisms. Some of them, NPs like Ag, Au and oxides of Al, Ti, Si and Zn have harmful effect on the cells of microorganisms. Iron NPs are expected to be nontoxic, due to using Fe atom in several pathways of cell metabolism and, therefore, low iron toxicity. The use of iron NPs in technologies for remedying polluted environment was caused by their efficiency in reduction reactions, mobility, and high reactivity, due to the high surface area. The present study aims to determine the effect of magnetite (Fe3O4), zero-valent iron Fe(0) NPs, and fluorinated dinitroaniline herbicide trifluralin on growth of mycelial fungi. Fungal strains were isolated from soil long-term polluted with obsolete pesticides, DDT and trifluralin. The inhibition activity of iron NPs and trifluralin was evaluated using express-method. Each fungal strain had an individual reaction to the solutions of iron nanoparticles. At the same time, Fe(0) NPs, as well as magnetite NPs, had a stimulating effect on the formation and maturation of spores of micromycetes. Addition of trifluralin to the culture medium had a growth inhibition effect on micromycetes, but this effect was reduced, when trifluralin was mixed and incubated with iron NPs for 1 hour before.

Utilisation of nanoparticles in technologies of producing castings for the needs of power engineering

Castings constitute important installation elements in the traditional coal, gaseous or nuclear power plants. Cast elements are also used in installations of the so-called renewable energy. Utilising nanoparticles in the foundry industry leads to improvements in the quality of produced castings and thus to the cost production lowering. Better properties of moulds and cores were achieved as a result of utilisation of nanoparticles in sand technologies. Works carried out in the Faculty of Foundry Engineering, AGH-UST, concerned the water-glass binder modification by nanoparticles of metal oxides (zinc oxide and magnesium oxide) in alcoholic solvents (methanol, ethanol and propanol). Nanoparticles were synthesised in the electrochemical process by anodic dissolution of metals as well as by the thermal method. The nanoparticles of zinc oxide obtained in the electrochemical process are of the structure of equiaxial agglomerates of various sizes depending on the applied alcohol. The largest nanoparticles were obtained from the methyl alcohol solution (~50 nm), while the smallest (≤20 nm) from the propyl alcohol solution. The highest tensile strength (above 25% larger than the strength of the moulding sand with no modified water-glass) was obtained by the moulding sand in which water-glass was the binder modified by the colloidal solution of zinc oxide nanoparticles in propyl alcohol.