The article presents the results of research which describes antagonism between Pb-Zn in selected plant species from the area of Czestochowa – Mirow district (north-western part of the Czestochowa Upland). There were analyzed changes in the ratio of Pb/Zn in different organs of the tested plants as a function of the Zn content changes. The content of metals in the plants and the soil was determined using atomic absorption spectrophotometry AAS. In all organs of the plants there was observed antagonistic decrease of Pb uptake and accumulation, resulting from the increase in the concentration Zn.
Antagonism between Zn and Pb in roots of the tested plants occurred at Zn content of 200–600 μg/g. In turn, antagonism in stems and flowers occurred at lower contents of zinc (100–180 μg/g). In leaves, antagonism between Pb and Zn occurred when Zn was present at the level of 300–800 μg/g.
Ex definition of the analyses confirm the presence of antagonism of lead with regard to high levels of Zn. The study also confirmed that the degree of antagonism depends on the plant species.
The granary weevil, Sitophilus granarius (L.), is one of the most important internal feeders of stored grain. Nanotechnology has become one of the most promising new approaches for pest control in recent years. In our screening program, laboratory trials were conducted to determine the effectiveness of silica nanoparticles (SNPs) and zinc nanoparticles (ZNPs) against the larval stage and adults of S. granarius on stored wheat. Nanoparticles of silica and zinc were synthesized through a solvothermal method. They were then used to prepare insecticidal solutions of different concentrations and tested on S. granarius. Silica nanoparticles (SNPs) were found to be highly effective against S. granarius causing 100% mortality after 2 weeks. ZNPs were moderately effective against this pest.
An analysis of the effect of drawing speed on the formation of a zinc coating in the multi-stage fine steel wire drawing process has been carried out in the article. Pre-hardened 2.2 mm-diameter material was drawn into 1.00 mm-diameter wire in 6 draws on a multi-stage drawing machine. The drawing process was carried out at a drawing speed of 5, 10, 15, 20 and 20 m/s, respectively. Mechanical tests were tests were performed for the final wires to determine their yield strength, ultimate tensile strength, uniform and total elongation and reduction in area. The thickness of the zinc coating on the wire surface was determined by the gravimetric method and based on metallographic examination. The use of electron scanning microscopy, on the other hand, enabled the identification of individual phases in the zinc coating. The above investigations were supplemented with corrosion testing of 1.00 mm-diameter wires. It has been demonstrated that drawing speed significantly influences not only the thickness of the zinc coating on the drawn wire surface, buts also its morphology and corrosion resistance.
To obtain anti-corrosive thermo-diffusion zinc coatings, the authors use highly effective zinc saturating mixtures. This technology makes it possible to obtain coatings with a high zinc content in the δ-phase as well as a zinc-rich phase of FeZn13 (ζ-phase) on the coating surface. As a result of long-term studies into the corrosion properties of thermo-diffusion zinc (TDZ) coatings conducted by the authors, a number of features of their corrosive behavior have been established. The corrosion rate of those coatings in desalted and chloride-containing media is lower than those of galvanic or hot-dip zinc coatings. The corrosion behavior depends on the content of zinc on the surface and the texture features of the coating. The results showed that on the surface of thermo-diffusion coatings in the corrosion on media containing chloride ions, zinc hydroxychloride (simonkolleite – Zn5Cl2[OH]8[H2O]) has been formed. Compared to coatings obtained by other methods, the rate of simonkolleite formation was higher on TDZ coatings, which might have a positive effect on their resistance in aggressive atmospheres.
The article presents the results of plasma vitrification of solid remnants from thermal waste treatment with and without the addition of a carbonate fraction obtained from lead-zinc ore flotation. The substrates used in the research were slags and ashes from medical waste treatment, incineration of municipal waste, sewage sludge as well as hazardous and industrial wastes.
The plasma treatment resulted in acquiring products of different quality depending on the processed substrate. Most of the obtained products were of vitreous and homogenic build. Treatment of remnants from incineration of hazardous and industrial wastes resulted in obtaining heterogeneous and rough surfaced products. A 20% share of the carbonate fraction enabled the obtaining of a vitrified product with a glassy surface and fracture. Hardness of the obtained products was rated in Mohs scale and ranged from 6 to 6,5. Leaching tests showed a decrease in heavy metal concentration in the leachates from vitrificates with the addition of carbonate fraction compared to the ones with it.
The aim of this study was to determine the effect of different zinc and iron concentrations in culture
medium on growth and development of maize and wheat seedlings in terms of their inoculation with bacteria of
Azospirillum genus. Maize and wheat in vitro cultures were inoculated, respectively, by strains of Azospirillum
lipoferum and Azospirillum brasilense strains. The experimental factor was the supplementation of the culture
medium with zinc (25, 200 and 600 mg·kg-1 of the medium) and iron (25, 200 and 600 mg·kg-1 of the medium).
Counts of bacteria from the Azospirillum genus were analysed and plant seedling growth and development as
well as the content of chlorophyll in plant leaf blades were monitored.
Zinc turned out to reduce strongly numbers of bacteria of the Azospirillum genus. Azospirillum brasilense
turned out to be particularly sensitive to elevated levels of this chemical element in the environment. The negative influence of increased quantities of zinc on cereal seedlings became apparent only after the application of
the highest concentrations of this metal in the medium (600 mg·kg-1), while quantities which did not exceed
200 mg·kg-1 exerted a stimulation effect on the mass of maize and wheat seedlings.
Iron added to the culture medium in quantities which did not exceed 200 mg·kg-1 did not reduce numbers of
bacteria of the Azospirillum genus; on the contrary, they stimulated their growth. However, at higher concentrations, this metal turned out to exert a strong negative impact on the chlorophyll content in leaf blades as well as
on the mass of maize and wheat seedlings.
The inoculation with bacteria of the Azospirillum genus exerted a positive influence on the mass increase of
maize and wheat seedlings and increased chlorophyll concentrations in leaf blades. At the same time, it contributed significantly to limiting or even levelling out the toxic impact of zinc and iron during the initial phases of
plant growth and development.
Water mint (Mentha aquatica L.) belongs to the arsenic tolerant plant species suitable for cultivation
in Central European climate conditions. Therefore, its possible application for remediation of contaminated soil
was investigated in pot and field experiments. Two M. aquatica plants of different origin, i) commercially market-available mint plants, and ii) plants habituated at the arsenic contaminated former mining area in southern
Tuscany (Italy) were tested for their arsenic uptake, transformation, and speciation. The total arsenic concentrations in the experimental soils varied from 21 to 1573 mg As kg-1, the mobile fractions did not exceed 2% of total
soil arsenic. The mint plants originating from the contaminated area were able to remove ~400 µg of arsenic
per pot, whereas the commercial plant removed a significantly lower amount (~300 µg of arsenic per pot). Only
arsenite and arsenate, but no organoarsenic compounds were identified in both stems and leaves. Arsenate was
the predominant arsenic compound and reached up to 80% regardless of the origin of the mint plants. Although
M. aquatica seems to be able to grow in contaminated soils without symptoms of phytotoxicity, its efficiency to
remove arsenic from the soil is limited as can be demonstrated by total elimination of As from individual pots
not exceeding 0.1%. Moreover, the application of plants originating from the contaminated site did not result in
sufficient increase of potential phytoextraction efficiency of M. aquatica. Although not suitable for phytoextraction the M. aquatica plants can be used as vegetation cover of the contaminated soil at the former mining areas
This work presents the results of a study whose aim was to determine the influence of algal blooms on precipitation of heavy metals. The scope of the study covered culture of a mixed population made up of Scenedesmus and Pseudokirchneriella algae in experimental conditions and initiating a metal biosorption process with the use of culture biomass by administering ions of Zn(II) and Ni(II). The process was controlled by assessing the level of biosorption of metals entered at a one-off basis in the form of Zn(II) and Ni(II) salts or in the form of mixture of both ions, in comparison to the control sample, at different exposure times (2 hours and 24 hours). The presence of metals was determined both in the biomass and in the culture medium. The presented results of the study confirm the effectiveness of Chlorophyta in the process of zinc and nickel biosorption. A phenomenon of competitiveness between the metals was observed when they were administered at the same time.
Dust generated at an electric arc furnace during steel production industry is still not a solved problem. Electric arc furnace dust (EAF) is a hazardous solid waste. Sintering of well-prepared briquetted mixtures in a shaft furnace is one of possible methods of EAFD utilisation. Simultaneously some metal oxides from exhaust gases can be separated. In this way, various metals are obtained, particularly zinc is recovered. As a result, zinc-free briquettes are received with high iron content which can be used in the steelmaking process. The purpose of the research was selecting the appropriate chemical composition of briquettes of the required strength and coke content necessary for the reduction of zinc oxide in a shaft furnace. Based on the results of the research the composition of the briquettes was selected. The best binder hydrated lime and sugar molasses and the range of proper moisture of mixture to receive briquettes of high mechanical strength were also chosen and tested. Additionally, in order to determine the thermal stability for the selected mixtures for briquetting thermal analysis was performed. A technological line of briquetting was developed to apply in a steelworks.
This paper analyses the heat treatment of the hot-dip zinc coating deposited on both cast iron and steel. The aim of research is to increase coating hardness and wear resistance without decreasing its anticorrosion properties. Hot-dip zinc coating was deposited in industrial conditions (acc. PN-EN ISO 10684) on disc shape samples and bolts M12x60. The achieved results were assessed on the basis of microscopic observation (with the use of an optical and scanning microscope), EDS (point and linear) analysis and micro-hardness measurements. It was discovered that the heat treatment of zinc coating results in an increase in hardness which is caused by the corresponding changes in microstructure.
The effect of cationic, anionic and nonionic surface active additives, organic compounds and polymers on the electrodeposition of Zn-Mo coatings on steel substrate and detailed characterization in chosen optimal conditions was studied. The influence of polyethylene glycol (PEG) various concentration, sodium dodecyl sulphate (SDS), triton X-100, d-sorbitol, cetyl trimethyl ammonium bromide (CTAB), thiourea and disodium ethylenediaminetetraacetate (EDTA) on the electrodeposition process was examined. The composition of deposits was defined by wavelength dispersive X-ray fluorescence spectrometry (WDXRF). Results has shown that the current efficiency of the electrodeposition of Zn-Mo coatings is 71.4%, 70.7%, 66.7% for 1.5 g/dm3 PEG 20000, 0.1 g/dm3 Triton X-100 and 0.75 M D-sorbitol respectively. The surface topography and roughness of selected coatings on steel was investigated by atomic force microscopy (AFM). The attendance of D-sorbitol of 0.75 M in the solution cause clear reduction of grain size and the value of roughness parameter (Ra) in relation to SDS, PEG, Triton X-100 and the sample prepared without the additives. The morphology of electrodeposited layers was studied by scanning electron microscopy (SEM). The addition of selected additives to the electrolytic bath results in the formation of smoother, brighter and more compact Zn-Mo coatings in comparison to layers obtained from similar electrolytes but without the addition of surfactants. The optimal concentration of the most effective additives such as PEG 20000, Triton X-100 and D-sorbitol is 1.5 g/dm3, 0.1 g/dm3, 0.75 M respectively.