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Number of results: 72
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Abstract

Concentration of Zn, Cu, Cd, Pb and Co have been determined in Antarctic water (South Shetland Islands) and in krill exoskeletons with the help of atomic absorption spectrophotometry. Concentrations of these metals both in sea-water and in krill exoskeleton are in order Zn > Cu > Cd > Ni > Pb > Co. Comparing concentrations of these metals in sea-water to their concentrations in krill exoskeleton, the factors have been calculated giving a list of metals in the order of krill chitin ability, which is Ni > Cu > Zn > Cd > Pb > Co accumulation. The highest accumulation factors for Ni and Cu point out to the special role played by these metals in krill life.
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Abstract

The contents of copper, manganese, zinc, lead and cadmium have been determined in plants of the Spitsbergen tundra, collected at Calypsostranda, Lyellstranda and Chamberlindalen in 1987. Five species of vascular plants, four species of mosses and fourteen species of lichens have been investigated. Manganese content in all the studied plants falls in the physiological limits of this element. Appreciable concentrations of copper, and zinc exceeding the physiological concentrations of these elements and presence of lead and cadmium have been shown for many plants.
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Abstract

Metal contents in the tundra soils (Gelic Regosols, Gelic Gleysols, Gelic Cambisols) of the maritime lowland of Kaffiöyra, in the western Spitsbergen seashore are presented in this publication. The average heave metal contents in samples collected from the depth layer 0—130 cm are follows: Fe 2.9%, Mn 392 ppm, Zn 75 ppm, Cu 23.4 ppm, Ni 24.1 ppm, Co 7.4 ppm, Pb 12.5 ppm, Cd 0.24 ppm. The surface soil layer 0 to 25 cm is poorer in Ca and Mg than the underlying layer 25 to 130 cm. The heave metal contents like Fe, Mn, Ni and Co, are also somewhat lower in the upper layer. The enrichment indices of Pb and Cd are equal in the surface soil layer 1.16 and 1.23 respectively. Correlation coefficients between each studied element and organic carbon, and, on the other hand, soil separates < 20 μm and < 2 μm are very low.
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Abstract

The results of studies on the air pollution and on the natural sedimentation from the atmosphere in the South Shetlands are (Admiralty Bay) are presented. The amount of dust in the air varied from 0.11 to 10.90 μg x m-3 (the mean being 3.70 μg x m-3). The total amount of substances transported from the atmosphere in the Admiralty Bay region was estimated at 12.7t x km-2 per year, whereas the precipitation transports some 2.5 t x km-2 per year in this region. Preliminary data on the contents of Cu. Cd. Co. Ni. Pb and Zn in the samples of surface waters, snow and rain in the region of the Admiralty Bay are presented and compared with the results of the authors.
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Abstract

In the years 1987-1995 studies were carried out on the content of Cu, Mn, Zn, Pb and Cd in plants and soil in the Bellsund area, Western Spitsbergen. For the studies the author used predominating species of vascular plants, bryophytes and lichens collected from beaches littoral planes, valleys, slopes and mountain peaks. Some plant species, largely bryophytes and lichens, were shown to contain increased amounts of Zn, Pb and Cd, whilst in others Cu deficiency was found. This paper is summing up studies concerning the content of Cu, Mn, Zn, Pb and Cd in plants of Western Spitsbergen, which were conducted over many years.
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Abstract

Distribution of the following elements: Na, K, Ca and Mg, and heavy metals: Fe, Mn, Zn, Cu, Ni, Co, Pb and Cd was analysed in the Gelic Cambisols profile from Kaffiöyra, Spitsbergen. The leaching of Ca, Fe, Mn, Co and Cu, and in a less degree Mg and Ni downward the profiles occurs in the studied soil due to pedogenic processes. The surface soil horizon is strongly enriched in Na and K of marine origin and Pb and Cd from anthropogenic pollution of the distant atmospheric transports.
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Abstract

The analysis of leaching behavior of harmful substances, such as arsenic, is one of the parameters of risk assessment resulting from the storage or economic use of coal waste. The leachability depends both on the environmental conditions of the storage area as well as on the properties of the waste material itself. There are a number of leaching tests that allow to model specific conditions or measure the specific properties of the leaching process. The conducted research aimed at comparing two methods with different application assumptions. The study of arsenic leaching from waste from the hard coal enrichment process was carried out in accordance with the Polish PN-EN 12457 standard and the US TCLP procedure. The leaching results obtained with both methods did not exceed the limit values of this parameter, defined in the Polish law. Both methods were also characterized by the good repeatability of the results. The use of an acetic acid solution (TCLP method) resulted in three times higher arsenic leaching from the examined waste compared to the use of deionized water as a leaching fluid (method PN-EN 12457). Therefore, the use of organic acid tests for mining waste intended for storage with municipal waste should be considered, as the results of the basic test based on clean water leaching may be inadequate to the actual leaching of arsenic under such environmental conditions.
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Abstract

The mathematical model and numerical simulations of the solidification of a cylindrical shaped casting, which take into account the process of filling the mould cavity by liquid metal and feeding the casting through the riser during its solidification, are presented in the paper. Mutual dependence of thermal and flow phenomena were taken into account because have an essential influence on solidification process. The effect of the riser shape on the effectiveness of feeding of the solidifying casting was determined. In order to obtain the casting without shrinkage defects, an appropriate selection of riser shape was made, which is important for foundry practice. Numerical calculations of the solidification process of system consisting of the casting and the conical or cylindrical riser were carried out. The velocity fields have been obtained from the solution of momentum equations and continuity equation, while temperature fields from solving the equation of heat conductivity containing the convection term. Changes in thermo-physical parameters as a function of temperature were considered. The finite element method (FEM) was used to solve the problem.
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Abstract

Ultrasonic processing in the cavitation mode is used to produce the composite materials based on the metal matrix and reinforcing particles of micro- and nano-sizes. In such a case, the deagglomeration of aggregates and the uniform distribution of particles are the expected effects. Although the particles can not only fragment in the acoustic field, they also can coagulate, coarsen and precipitate. In this paper, a theoretical study of processes of deagglomeration and coagulation of particles in the liquid metal under ultrasonic treatment is made. The influence of various parameters of ultrasound and dispersion medium on the dynamics of particles in the acoustic field is considered on the basis of the proposed mathematical model. The criterion of leading process (coagulation or deagglomeration) has been proposed. The calculated results are compared with the experimental ones known from the scientific literature.
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Abstract

Geopolymers are a new class of materials that can be synthesized using natural minerals, and waste materials. Among these substrates, the use of fly ash is desirable as it involves the conversion of a copious waste material into a useful product. The aim of the research was geopolymers synthesis from coal fly ash and biomass ash. Concentrated sodium hydroxide and sodium silicate solutions were used as activators in geopolymerisation reaction. The results show that both coal fly ash and biomass ash can be utilized as source materials for the production of geopolymers. The surface morphology and chemical composition analysis were examined for the obtained geopolymers and ashes from coal and biomass combustion by SEM-EDS methods. It was found almost total disappearance of spherical forms of grains and reduction the porosity of structure for geopolymer based on fly ash from coal combustion. While the structure of the geopolymer based ash from biomass combustion is more porous. The UV-VIS-NIR spectra were performed on the coal fly ash, biomass ash and geopolymers. They showed that the obtained geopolymers possess optical and photocatalytic properties. The similarity of the geopolymer network and the zeolite framework in relation to ion exchange and accommodation of metal ions open questions on possibilities for the application of geopolymer materials as amorphous analogues of zeolite. The FT-IR spectra analyses were used on the geopolymers before and after metals sorption. It was found that geopolymer based on ash from biomass combustion has better sorption properties compared to geopolymer based on ash from coal combustion.
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Abstract

The objective of the work are in-depth experimental studies of Cu(II) and Zn(II) ion removal on chitosan gel beads from both one- and two-component water solutions at the temperature of 303 K. The optimal process conditions such as: pH value, dose of sorbent and contact time were determined. Based on the optimal process conditions, equilibrium and kinetic studies were carried out. The maximum sorption capacities equaled: 191.25 mg/g and 142.88 mg/g for Cu(II) and Zn(II) ions respectively, when the sorbent dose was 10 g/L and the pH of a solution was 5.0 for both heavy metal ions. One-component sorption equilibrium data were successfully presented for six of the most useful three-parameter equilibrium models: Langmuir-Freundlich, Redlich-Peterson, Sips, Koble-Corrigan, Hill and Toth. Extended forms of Langmuir-Freundlich, Koble-Corrigan and Sips models were also well fitted to the two-component equilibrium data obtained for different ratios of concentrations of Cu(II) and Zn(II) ions (1:1, 1:2, 2:1). Experimental sorption data were described by two kinetic models of the pseudo-first and pseudo-second order. Furthermore, an attempt to explain the mechanisms of the divalent metal ion sorption process on chitosan gel beads was undertaken.
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Abstract

New technologies and the globalization of the electrical and electronic equipment market cause a continuous increase in the amount of electrical and electronic waste. They constitute one of the waste groups that grows the fastest in quantity. The development of the new generation of electrical and electronic devices is much faster than before. Recently attention has been concentrated on hydrometallurgical methods for the recovery of metals from electronic waste. In this article the role of an oxidizing agent, mainly ozone and hydrogen peroxide was presented in hydrometallurgical processes. Leaching process of printed circuits boards (PCBs) from used cell phones was conducted. The experiments were carried out in the presence of sulfuric acid and ozone as an oxidizing agent for various temperatures, acid concentration, ozone concentration. As a result, the concentrations of copper, zinc, iron and aluminum in the obtained solution were measured. The obtained results were compared to results obtained earlier in the presence of hydrogen peroxide as an oxidizing agent and discussed.
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Abstract

The broad range applications of Ultra-Fine Grained metals is substantially limited by the lack of a welding method that allows them to be joined without losing the strong refinement of structure. From this point of view, the solid state welding processes are privileged. Friction welding tests were carried out on UFG 316L stainless steel. A joining process at high temperature activates the recrystallization, therefore the friction welding parameters were selected according to the criterion of the lowest degree of weakness due to recrystallization in the heat affected zone. In order to characterize the structure of basic material and selected areas of the obtained joint, were performed SEM, TEM and metallographic examinations in terms of hardness and range of softening of the material and tensile test. Despite the short time and relatively low welding temperature, results of the test by scanning electron microscopy and transmission electron microscopy confirmed the loss of the primary ultrafine structure in the Heat Affected Zone of welded joint.
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Abstract

Trials of cast steel filtration using two types of newly-developed foam filters in which carbon was the phase binding ceramic particles have been conducted. In one of the filters the source of carbon was flake graphite and coal-tar pitch, while in the other one graphite was replaced by a cheaper carbon precursor. The newly-developed filters are fired at 1000o C, i.e. at a much lower temperature than the currently applied ZrO2-based filters. During filtration trials the filters were subjected to the attack of a flowing metal stream having a temperature of 1650°C for 30 seconds. Characteristic of the filters’ properties before and after the filtration trial were done. It was found, that the surface reaction of the filter walls with molten metal, which resulted in local changes of the microstructure and phase composition, did not affect on expected filter lifetime and filtration did not cause secondary contamination of cast steel.
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Abstract

The levitation melting has a potentially wide range of applications, especially in the processing of reactive metals whose contact with the crucible material causes their contamination and damage to the crucible itself. Despite its advantages, levitation melting, already proposed in the 1920s, has not yet found significant use in industrial conditions. This is due to the nature of the electromagnetic field used in previously developed devices. The disappearance of this field in the system axis causes overcoming, in the case of larger charges, surface tension forces and metal leakage from the device. The article contains a comparative analysis of a conventional solution and a newly developed levitation melting device, whose completely different design eliminates the previous weight limit of the charge.
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Abstract

Heavy metal (As, Mn, Ni, Sn, Ti) concentrations were determined in soil and plant samples collected in different areas of the railway junction Iława Główna, Poland. Soil and plant samples were collected in four functional parts of the junction, i.e. the loading ramp, main track within the platform area, rolling stock cleaning bay and the railway siding. Four plant species occurring in relatively higher abundance were selected for heavy metals analysis, although in the loading ramp and platform areas only one species could be collected in the amount which makes chemical analysis possible. The selected species included three perennials (Daucus carota, Pastinaca sativa and Taraxacum officinale) and one annual plant (Sonchus oleraceus). The entire area of the railway junction showed elevated concentrations of heavy metals when compared to the control level. It was most pronounced for the platform area and railway siding. The concentration of arsenic, manganese and nickel in plants growing in these parts of the junction exceeded the toxic level. The highest contamination of soil and plants found in the platform area suggested advanced emission process of the analyzed metals from wheel and track abrasion. Literature review showed that the concentration of the investigated metals in soil was generally higher than that found in centers of cities and along traffic roads proving that the railway is an important linear source of soil contamination
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Abstract

This study was undertaken to determine the effectiveness of biosurfactants - saponin, tannin and rhamnolipids JBR 515 and 425, for the removal of cadmium, zinc and copper from activated sludge immobilized in 1.5% sodium alginate with 0.5% polyvinyl alcohol. We also established the impact of pH value on biosorbent regeneration with the analyzed biosurfactants and determined the critical micelle concentration (CMC) in solutions containing the biosorbent and biosurfactant and in exact samples with heavy metals. Saponin exhibited the highest effectiveness of metals leaching at pH 1-5, and rhamnosides at pH 5-6. In addition, the study demonstrated a significant effect of the ratio of biosorbent mass to washing agent volume (m/V) on the effectiveness of metals leaching. Of the biosurfactants analyzed, saponin was ca. 100% effective in leaching zinc and copper. The effectiveness of the other biosurfactants was lower and depended on the metal being leached
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Abstract

Vegetable oils belong to a large group of substances consumed on a daily basis. World vegetable oil production is soaring, reducing the popularity of animal fats. Heavy metals pose a threat to human health. It is estimated that about 80% of the daily dose of heavy metals enters the human body through the consumption of food. Hence, it is necessary to monitor their concentrations in food products. Besides, the presence of heavy metals is thought to have possible negative influence on the quality of oils, especially on their taste and smell. Heavy metals may also accelerate the process of the rancidifiction of oils. Rapeseeds, soybean seeds and linseeds were selected for the analysis because they are one of the most popular oilseeds and at the same time they differ in terms of growing conditions. The analyses of different fractions and the ready-made product were also performed. The aim of the study was to determine the variation in concentrations of heavy metals, iron and manganese in different fractions during production. The significant concentrations of iron, manganese and zinc were observed in oilseeds. It was also shown that during different stages of oil refining the concentrations of metals decrease. The concentrations of metals are compared with those reported in literature.
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Abstract

Soils that have been exposed to flood waters can be heavily polluted by inorganic and organic compounds. They are mainly compounds which appear in dissolved or suspended form flowing together with heavily laden floodwater, as well as compounds created as a result of reactions in the soil profile, mostly due to anaerobic transformation of organic matter. Heavy metals brought with flood waters are absorbed by the soil and also washed out from flood sediments by precipitation when the flood recedes. This paper presents the results of research on the effects of fertilization with ash from incineration or pyrolysis of biomass on the migration process of heavy metals (Zn, Cu, Cr, Ni, Pb, Cd, Mn) in the arable layer of soil. It has been shown that the metals in the flood sediment migrate actively in the soil profile what leads to the enrichment of the soils, also in the case of the soil fertilization with biomass ash.
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Abstract

Serpentine soils from 16 sample points in Serbia as well as the roots and shoots of eight Brassicaceae family species: Aethionema saxatile, Alyssum montanum, Alyssum repens, Cardamine plumieri, Erysimum linariifolium, Erysimum carniolicum, Isatis tinctoria, Rorippa lippizensis, were analyzed with regard to their concentrations of P, K, Fe, Ca, Mg, Ni, Zn, Mn, Cu, Cr, Cd, and Pb. Most of the soil samples were typical of ultramafic sites with low concentrations of P, K and Ca and high concentrations of Mg, Fe, Ni and Zn. Ca/Mg ratio was <1 in most soil samples and Brassicaceae plants. Only in A. montanum, A. repens, E. linariifolium and R. lippizensis was the Ca/Mg ratio >1. The levels of P, K, Fe and Zn were high, Mn and Cu occurred in low amounts, whereas Cr, Cd, Co and Pb were only traceable. In the roots and shoots of A. montanum and A. repens the measured concentrations of Ni were 657 mg kg-1 and 676 mg kg-1 respectively, which is the first instance that such high concentrations of Ni were detected in these two species.
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Abstract

The aim of this work was to determine the effect of various cadmium and copper concentrations on the activated sludge dehydrogenase activity. The investigations were carried out in six aerated chambers with activated sludge, volume of 1L each, by the continuous culture method (one control chamber, not contaminated with heavy metals and five with 0.5; 1; 2; 4; 8 mg L-1 Cu+2 and 0.1; 0.3; 0.9; 2.7; 8.1 mg L-1 Cd2+). Cadmium sulfate and copper sulfate as a source of heavy metals were used. The concentrations of these metal ions, causing 50% dehydrogenase activity inhibition were determined. The particular attention was paid to the toxic effect of metal ions, as well as the variations of the microbial respiration activity proceeded during toxins exposition. The investigation showed that even the lowest concentration of the investigated metal ions caused significant changes of the activated sludge dehydrogenases activity. Copper ions showed to be more toxic than cadmium ions.
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Abstract

The aim of this study was to identify a suitable lichen species for the long−term monitoring of heavy−metal atmospheric pollution in Svalbard. Cladonia and Cetraria s.l. species that have been widely used until now for assessing heavy−metal deposition in the Arctic are in decline over extensive areas of Svalbard, mainly due to climate change and over−grazing by reindeer. Cetrariella delisei , rarely used for biomonitoring, is still common and widespread in this area. Levels of Cr, Ni, Fe, Cu, Pb, Zn, Cd and Mn were measured in three lichen species: Cetrariella delisei , Cladonia uncialis , Flavocetraria nivalis and in a moss Racomitrium lanuginosum from Sørkapp Land, South Spitsbergen. The results imply that Cetrariella delisei can be safely compared to Cladonia uncialis for identifying the levels of heavy metals, but direct comparison between Cetrariella delisei and other species studied is more difficult owing to differences in levels of heavy metals even in samples from the same site.
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Abstract

The study investigates chemical modifications of coal fly ash (FA) treated with HCl or NH4HCO3 or NaOH or Na2edta, based on the research conducted to examine the behaviour of Cd(II) and Pb(II) ions adsorbed from water solution on treated fly ash. In laboratory tests, the equilibrium and kinetics were examined applying various temperatures (293 - 333 K) and pH (2 - 11) values. The maximum Cd(II) and Pb(II) ions adsorption capacity obtained at 293 K, pH 9 and mixing time 2 h from the Langmuir model can be grouped in the following order: FA-NaOH > FA-NH4HCO3 > FA > FA-Na2edta > FA-HCl. The morphology of fly ash grains was examined via small-angle X-ray scattering (SAXS) and images of scanning electron microscope (SEM). The adsorption kinetics data were well fitted by a pseudo-second-order rate model but showed a very poor fit for the pseudofirst order model. The intra-particle model also revealed that there are two separate stages in the sorption process, i.e. the external diffusion and the inter-particle diffusion. Thermodynamics parameters such as free energy, enthalpy and entropy were also determined. A laboratory test demonstrated that the modified coal fly ash worked well for the Cd(II) and Pb(II) ion uptake from polluted waters.
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