Increase In Sulfur Content Research Articles

Carbon-Dioxide and Hydrogen-Sulfide Removal from Simulated Landfill Gas Using Steel Slag

Municipal solid waste landfills are a source of major greenhouse gases such as methane (CH4) and carbon dioxide (CO2) and emit a trace amount of hydrogen sulfide (H2S). Recently, steel slag has extensively been used for mineral CO2 sequestration to minimize the CO2 releases to the atmosphere. This study explores the potential of basic oxygen furnace (BOF) steel slag to simultaneously remove CO2 and H2S from landfill gas (LFG). Various batch and column tests were conducted to evaluate the CO2 and H2S removal potential of the BOF slag under various conditions such as moisture content and particle size of the BOF slag. The three different particle sizes of BOF slag (coarse, as-is, and fine) were exposed to continuous flow of a synthetic LFG [50% CO2, 48.25% CH4, and 1.75% H2S by volume (v/v)] in a column reactor to evaluate the effect of particle size on CO2 and H2S removal capacity of the slag. Similarly, the BOF slag was exposed to synthetic LFG as well as 20% (v/v) of H2S alone in batch reactors at varying moisture contents (10%–30% by weight) to evaluate the effect of moisture content on the CO2 and H2S removal capacity of the slag. A significant H2S removal of 27 g H2S kg−1 BOF slag and CO2 removal of 76 g CO2 kg−1 BOF slag were obtained in the batch reactor. The fine BOF slag (<0.106 mm) showed the maximum CO2 removal (300 g CO2 kg−1 BOF slag) and H2S removal (38 g H2S kg−1 BOF slag) upon exposure to continuous synthetic LFG flow in the column reactor. The quantitative X-ray diffraction (QXRD) analysis showed the highest increase in carbon (77.5 g C kg−1 BOF slag) and sulfur (28 g S kg−1 BOF slag) contents in the fine BOF slag, which was consistent with the mass balance of carbon and sulfur from CO2 and H2S uptake in column tests. The major reaction product with H2S was elemental sulfur depicted by the significant increase in the sulfur content in the X-ray fluorescence analysis. The key minerals involved in carbonation reactions were lime, portlandite, and larnite, as these minerals showed significant reduction in weight percentage (100%, 82%, and 80%, respectively) in the QXRD analysis. Overall, BOF slag showed promising results in mitigating CO2 and H2S from LFG.

Correlation of total sulfur content to the percentage of pyrite content by microscopy in Mallawa formation coal, South Sulawesi Province, Indonesia

The Mallawa Coal Formation in general, has a high sulfur content even though the calorific value is quite high. Deposition environment will affect the sulfur content in coal. This study aims to determine the relationship of sulfur content to the percentage of pyrite mineral content in coal by microscopy. The research method used is field data collection, each using the channel sampling method (ply by ply) in Pujananting Barru Regency and Massenrengpulu Bone regency. Then a proximate and petrographic analysis was carried out to obtain sulfur content, and the percentage of pyrite in coal. The analysis shows that coal in the Pujananting area shows no relationship correlation between total sulfur content in coal and the percentage of pyrite minerals, so it can be concluded that sulfur in Pujananting coal is organic sulfur, which is formed together with the formation of coal starting during the peat process. While Massenrengpulu coal shows a correlation and relationship between the increase in sulfur content and the increase in the percentage of pyrite minerals, it can be concluded that the sulfur content in Massenrengpulu coal is derived from pyritic sulfur, which is strongly influenced by the depositional environment where the coal is formed.

The effect of sulfur content of rotary kiln fuel on the composition of nickel laterite calcine

Rotary kiln-electric furnace (RK-EF) process is the main pyrometallurgical route for ferronickel production from nickel laterite ores. Coal is used as a common fuel for calcination of nickel laterites in rotary kiln. Due to the depletion of high-quality coal with low impurity content, high-sulfur coal has been used as fuel in nickel laterite rotary kilns. This investigation examines the behavior of sulfur present in the rotary kiln fuel in the calcination stage. Using coal with higher sulfur content, improving the reducing atmosphere in the furnace, and increasing the fuel consumption result in an increase in sulfur content of the nickel laterite calcine. Higher sulfur deportation from the gas phase to the calcine was observed by raising the temperature from 600 to 800 °C; however, increasing the temperature to 900 °C decreases the sulfur deportation percentage due to the recrystallization of the silicate compounds. Iron sulfide was identified as the main sulfur-containing compound in the calcine.

Pyrolysis of fatty acids derived from hydrolysis of brown grease with biosolids

The escalating generation of biosolids and increasing regulations regarding their safe handling and disposal have created a great environmental challenge. Recently, biosolids have been incorporated into the hydrolysis step of a two-step thermal lipid conversion process to act as water replacement in the production of renewable chemicals and fuels. Here, the hexane extract recovered from hydrolysis of biosolids, lipids from brown grease hydrolyzed using either water (control) or biosolids as a water replacement, was pyrolyzed at 410–450 °C for 2 h. The product distribution and composition were not significantly different when biosolids were used to hydrolyze brown grease instead of water. The liquid product consisted mainly of alkanes, alkenes, aromatics, and cyclic compounds similar to those in petroleum-derived liquid fuels. However, the use of biosolids as a water substitute resulted in a significant increase in sulphur content of the pyrolysate, which will necessitate processes to reduce the sulphur content before or after pyrolysis. Nevertheless, the pathways proposed in this paper are considered as potentially economically viable approaches to not only resolve the issues associated with disposal of biosolids but also to produce renewable hydrocarbons for fuel and chemical applications.Graphical abstract

Effect of Composition, Microstructure and Hardness after Heat Treatment on Machinability of Steel Forgings

Machining is a major process performed on the forged steels. Any change in composition or heat treatment of these steels changes their microstructure as well as properties. Knowing the limited focus on understanding the machinability of forging steels, this study focuses on comparison of dry machinability of ferritic-pearlitic, quench-tempered and bainitic steels under different cutting conditions with a variation in its composition and heat treatment performed on them. The machinability in the dry condition is assessed in terms of cutting and thrust forces, machining temperature, tool abrasion wear on the flank face of tools and chip segmentation. In ferritic-pearlitic steels, prominent mode of chip segment formation is Mode-II fracture (shearing), whereas in the quench-tempered steels, it changes from Mode-I (tearing) to Mode-II (shearing) as the sulfur content increases. In the case of bainitic steels, Mode-I fracture is often prominent. The ferritic-pearlitic and quench-tempered steels depict a reduction in cutting forces in between 5 and 12% and machining temperature in between 12 and 20% due to addition of sulfur even though its strength is higher due to higher vanadium content.

Investigating the effects of hemicellulose pre-extraction on the production and characterization of loblolly pine nanocellulose

Production of nanocellulosic materials from loblolly pine (Pinus taeda) kraft pulp provides an opportunity to diversify the portfolio of traditional pulp and paper industries. In this study, pinewood was first subjected to dilute acid pre-extraction with 0.5% sulfuric acid in order to fractionate the hemicellulose, followed by kraft pulping and elemental chlorine free bleaching in order to obtain up to 97% pure cellulose fractions. CNCs (cellulose nanocrystals) were prepared by hydrolyzing the bleached kraft pulp with 64% sulfuric acid at 45 °C for 30 min; the resultant unhydrolyzed solid residues were homogenized using a microfluidizer in order to produce cellulose nanofibers (CNFs). The dilute acid pre-extraction step resulted in complete hydrolysis of galactan and arabinan from pinewood, as well as in partial removal of mannan (80%) and xylan (58%). As a result of pre-extraction, the CNC yield and crystallinity improved by 44% and 11%, respectively, from the corresponding kraft pulps. CNCs produced from the pre-extracted materials also exhibited 16% reduction in particle size, but a 70% increase in sulfur content as well as 20% increase in zeta potential. Higher purity of kraft pulps resulted in higher exposure of cellulose crystalline domains to sulfuric acid thereby resulting in the observed changes. Thus, pulp purity was found to play a significant role in determining the quantity and quality of nanocellulosic materials derived from loblolly pine.

Structural and Optoelectronic Properties of Zinc Sulfide Thin Films Synthesized by Co-Precipitation Method

Abstract Wide bandgap Zinc Sulfide nanocrystals are prepared by a simple co-precipitation method at different precursor concentrations. The influence of sulphur concentration in Zinc sulfide on morphological, optical and electric properties is found to be significant. The Zinc Sulfide nanomaterial was prepared using low-cost starting materials and deionised water as the solvent. As synthesized Zinc Sulfide nanocrystals were analyzed using X-ray diffraction (XRD), Energy Dispersive Spectroscopy (EDS) analysis, UV-Visible Spectrophotometry, Photoluminescence (PL), Scanning electron Microscopy (SEM), Ellipsometry techniques and electric conductivity measurements. XRD patterns revealed that ZnS nanocrystals are polycrystalline, cubic phase with (111) preferred orientation. The obtained crystallites have sizes in the range of 5 to 11 nm. EDS pattern confirms the purity of the films. From optical absorption measurements, it is clear that the direct energy gap decreases from 5.2 to 4.4eV with the increase in sulphur concentration in ZnS and exhibit large quantum confinement effect. Ellipsometry was used to determine the optical constants and film thickness. The films deposited on ITO – coated glass was used to record the IV Characteristics of the films by two probe method. The wide-bandgap, conducting materials have applications in optoelectronic devices such as high-frequency UV detectors and thin-film solar cells.

Effect of dietary corn gluten inclusion on rumen fermentation, microbiota and methane emissions in goats

The study was to evaluate replacing corn meal (CM) by corn gluten (CG) on intake, digestibility, ruminal fermentation, CH4 emissions and microbial abundance in goats. The experiment was performed using randomized block design with 2 dietary treatments (CM and CG with 400 g/kg DM each). Replacing CM with CG increased NDF and CP intake and decreased starch intake. Goats fed CG diet had lower ruminal dissolved hydrogen (dH2) (-43%, P = 0.009) and dissolved methane (dCH4) (-30%, P = 0.001) concentrations than those fed with CM diet. An interaction between treatment and time (P = 0.03) was observed for dH2S with an increase (P < 0.001) in dH2S concentration (CG versus CM, +63%, P < 0.001) happened at 2.5 h after morning feeding. Goats fed with CG diet had lower (P = 0.004) butyrate molar percentage, and greater (P < 0.01) ammonia concentration and molar percentage of valerate and isobutyrate than those fed with the CM diet. Goats fed with CG diet decreased (P = 0.01) CH4 emission expressed as g/d and g/kg DMI. Goats fed with CG diet decreased 16S rRNA gene copies of R. amylophilus (P = 0.003), and increased 18S rRNA gene copies of fungi (P = 0.05) and 16S rRNA gene copies of F. succinogenes (P = 0.03). In summary, replacing CM with CG decreases starch and increases fiber intake, and growth of fibrolytic fungi and F. succinogenes, and inhibits growth of R. amylophilus. An increase in sulfur content after replacing CM with CG provides additional H2 sink, which causes an increase in ruminal dH2S and reduction in CH4 emissions. Corn gluten could be an alternative feed to decrease the enteric CH4 emission in ruminant production.

Effect of synthesis parameters on the structural, optical, morphological and electrical properties of n-type CTS nanostructures

In this work we have prepared n-type copper tin sulphide (CTS) quantum dot thin films for efficient window layers of solar cells. The change in type of CTS was achieved by the use of Triethanolamine (TEA) as the complexing agent. Studies were made on CTS thin films by changing the amount of complexing agent and also by changing the Cu:Sn and S:Sn ratios. All the samples showed low absorbance and high transmittance in the visible and infra red regions. The bandgaps are high enough to be used in buffer layers. Increasing the amount of TEA increased the crystallite size and thereby decreased the bandgap. Presence of excess copper in the material enhanced the conductivity of the material largely and also lead to the formation of Schottky barriers making Cu rich samples useful in rectification too. Increased sulphur content has been found to improve the crystallinity of CTS thin films.

Effect of Composition on The Structural, Morphology, and Optical Properties of AgSb(SxSe1-x)2Thin Films

Quenching method was used to prepare alloys of the AgSb(SxSe1-x)2 quaternary compound with different sulfur content. AgSb(SxSe1-x)2 thin films with different sulfur concentration were prepared at room temperature 303K on glass substrate using pulsed laser deposition under vacuum of 10−2 bar, thickness of ∼100nm. The structure of the prepared alloys and thin films were examined by x-ray diffraction. The results declared that all the prepared compounds have polycrystalline with cubic structure whereas the deposited AgSb (SxSe1-x)2 thin films were amorphous. Atomic Force Microscopy revealed that the average grain size decreases while roughness exhibit to increase in non-regular manner with the increase of sulfur concentration. The absorbance and the transmittance were provided from- visible spectrophotometer measurements in the wavelength range (300-1100nm). The results showed that the prepared thin films have indirect allowed band gap which showed absorbable increase with the increase of sulphur content, indeed the optical energy gap increase from 1.1 to 1.7 eV with the increase of sulphur content while all the optical constants (the refractive index n, the extinction coefficient k and real and imaginary parts of dielectric constants εr, εi all declared reduction with the increase of sulfur concentration.

Synthesis, characterization and dye-sensitized solar cell application of Zinc oxide based coaxial core-shell heterostructure

In the present work, the ZnO/CdS coaxial core–shell heterostructure has been synthesized on indium doped tin oxide glass substrate using chemical solution methods and further it is used as photoanode in the DSSC application. Four samples with different concentration of sulphur source were prepared. The approximate crystallite size of 22 nm for ZnO and 18 nm for CdS has been obtained as analyzed from x-ray diffraction data. FESEM and HRTEM images confirm the formation of CdS shell on ZnO nanorods with a width below 100 nanometer. UV-visible spectroscopy and photoluminescence spectroscopy were used to examine the optical response revealing the fact that bandgap reduction and a small redshift takes place for core–shell structure as compared to bare ZnO nanorods array. The J-V characterization was performed to study the photovoltaic response. Improved efficiency was observed for core–shell ZnO/CdS heterostructure (3.66%) as compared to bare ZnO nanorods based DSSCs (0.70%). This improvement is due to increased current density caused by reduced recombination of photogenerated electron hole pairs. This reduced recombination is achieved by two factors, one is the formation of type two core–shell heterostructure and second is increasing sulphur concentration in shell structure.

Transformation and regulation of sulfur during pyrolysis of coal blend with high organic-sulfur fat coal

Sulfur transformation and distribution during pyrolysis of an industrial coking coal blend with a high organic-sulfur fat coal was studied in a fixed-bed reactor. Sulfur K-edge X-ray absorption spectroscopy was used to study the sulfur speciation in cokes. Two coals with high volatiles were selected to regulate the sulfur transformation behavior during pyrolysis and the interactions between volatile matters and nascent cokes were investigated. The addition of high organic-sulfur fat coal to coal blend resulted in the increase of sulfur content in coke, but the desulfurization rate also increased during coal blend pyrolysis. Higher amount of sulfur-containing radicals in volatile matters from high organic-sulfur fat coal promoted the interactions with nascent coke and resulted in the higher sulfur retention on the coke surface. Adding high volatile coal into coal blend affected the interactions between different coals and the sulfur transformation. The interactions between sulfur-containing radicals and nascent coke could be inhibited by volatile matters from high volatile coals. Further characterizations confirmed that the volatile matters from high volatile coal, which had a more overlapping temperature range to sulfur release in coal blend, leading to the lower sulfur content in coke, higher desulfurization and weaker S K-edge spectral intensity. The interactions between external volatile matters and nascent coke primarily occurred on the coke outer surface.

ABOUT THE CONDITIONS OF BLAST FURNACE SMELTING OF PIG IRON OF A CERTAIN QUALITY

The impact of operating conditions on the quality of pig iron has been investigated on a blast furnace with a volume of1500 m3at an average cost of pulverized coal up to160 kg/ ton of pig iron. It has been established that the influence on the content of silicon in cast iron by changing the slag regime has limited possibilities. In contrast to silicon, the change in the slag regime, primarily the basicity of the effective effect on the transition of sulfur to the slag. When designing optimum for specific conditions, the technology of blast-furnace smelting should take into account the difference in the behavior of silicon and sulfur when the heating of the furnace is changed, in particular, the content of sulfur in the pig iron varies faster than the content of silicon. The decrease in the temperature of the iron from 1500 to 1400oC was accompanied by an average decrease in the content of silicon from 0.89 to 0.47%, that is, approximately twice. The same decrease in temperature led to an increase in sulfur content in the metal, on average, from 0.013 to 0.042% or more than three times. Given this difference, depending on the possibilities of further processing of cast iron, it is necessary to establish such a thermal regime, which maintains the desired levels of sulfur and silicon content, providing a certain effect in the blast furnace process and further processing. The existence of a feedback between the intensity of the smelting and the content of silicon in the pig iron is established. The existence of pulsations of the average level of sulfur content in cast iron has been confirmed. An essential difference between our observations is an increase in the period of pulsations from 3-7 to 8-11. The reasons for increasing the period require further study.

The relationship between atmospheric pollutant emissions and fuel qualities of inland vessels in Jiangsu Province, China

ABSTRACTAir pollution caused by ship exhaust emission is receiving more and more attention. The physical and chemical properties of fuels, such as sulfur content and PAHs content, potentially had a significant influence on air pollutant emissions from inland vessels. In order to investigate the effects of fuel qualities on atmospheric pollutant emissions systematically, a series of experiments was conducted based on the method of actual ship testing. As a result, SO2, PM and NOx emission rates all increased with the increase of main engine rotating speed under cruise mode, while PM and NOx emission factors were inversely proportional to the main engine rotating speed. Moreover, SO2 emission factor changed little with the increase of the main engine rotating speed. In summary, the fuel-dependent specific emission of SO2 was a direct reflection of the sulfur content in fuel. The PM emission increased with the increase of sulfur content and PAHs content in fuel. However, fuel qualities impacted little on NOx emissions from inland vessels because of NOx formation mechanisms and conditions.Implications: Ship activity is considered to be the third largest source of air pollution in China. In particular, air pollutants emitted from ships in river ports and waterways have a direct impact on regional air quality and pose threat on the health of local residents owing to high pollutants concentration and poor air diffusion. The study on the relationship between air pollutant emissions and fuel quality of inland vessels can provide foundational data for local authority to formulate reasonable and appropriate policies for reducing atmospheric pollution due to inland vessels.

Reactivity and spontaneous combustion characteristics of high-sulphur coal during low-temperature oxidation

This study investigated the spontaneous combustion characteristics and the microscopic reaction mechanism of high-sulphur coal during low-temperature oxidation. Five coal samples with different levels of sulphur content (including 3.13, 4.18, 5.06, 6.28 and 7.00%) were selected and experiments were conducted with a temperature-programmed system and Fourier transform infrared spectroscopy (FTIR). It was shown that the O2 consumption rate, CO and CO2 production rates all rose with increased sulphur content, while they gradually fell after the sulphur content exceeded 5.06%. Conversely, when the sulphur content went up, the apparent activation energy dropped and showed a minimum at a sulphur content of 5.06% and was higher thereafter. The key functional groups participating in the oxidation reaction before the critical temperature was reached were methyl and carbonyl. Furthermore, the key functional groups were alkyl ether and carbonyl before and after the crack temperature, respectively. [Received: July 6, 2018; Accepted: September 24, 2018]

Integrated influence of melting parameters of rail steel on rail products quality and technical and economic indicators of the production

Analysis of literature and production data has shown that despite the significant improvement in quality of domestic rail products, achieved in the last decade due to fundamental technical re-equipment of rail production, there is a problem of increased rejection of rails for surface defects. Based on studies of influence of rail steel chemical composition on quality of rails produced by «EVRAZ ZSMK», there was established a significant effect of increasing copper content in the range of 0.07 - 0.15 % and of sulfur - in the range of 0.006 - 0.011 % in E76KhF steel to increase rejection caused by rail surface defects. Mechanism of the influence of these elements concentration in rail steel on finished rails quality was revealed. Decisive influence of ratio of pig iron and scrap in metal charge on copper and sulfur content in rail steel was evidenced - higher rate of cast iron in metal charge within 20 - 50 % contributes to decrease of copper concentration and increase of sulfur content. To justify optimal composition of the charge for rail steel melting in regard to rail products quality and technical and economic indicators of production, study of the effect of cast iron (liquid and solid) to scrap ratio in metal charge on basic parameters of furnaces’ operation was conducted. As a result, it was found that with an increase in share of both liquid and solid iron in metal charge, there are linear decrease in specific electricity consumption, increase in specific oxygen consumption according to parabolic law and a linear decrease in manganese content in furnace output. The obtained dependences of melting duration on ratio of charge components in metal charge indicates presence of prominent minimum, when using liquid iron in the range of 35 - 40 %, and when using solid iron - in the range of 30 - 35 %. Based on the regression equations, statistical model was constructed for the influence of metal charge composition on technical and economic performance of the melt charge in rail steel smelting, in which optimization parameters are: total cost, depending on the metal stock composition and performance of the shop for suitable billets produced by continuous casting. Application of the obtained model allows to develop reasonable recommendations on the optimal proportion of iron in the metal for current level of prices for materials and energy used in electric smelting, taking into account changes in the shop productivity.

Cationic and anionic modification of CdS thin films by surface chemical treatment

Structural and physical properties of thin solid films can be modified by surface treatment. In this work, chemical bath deposited CdS thin films were treated both by a mercury chloride solution and by a saturated H2S gas. The effect of these treatments on electrical properties is clearly observed. Hg2+ doped CdS films show the highest dark and photo-conductivities, whereas the sulfurized CdS films become photo-insensitive. In Hg2+ doped CdS samples, new crystalline Hg3S2Cl2 and Hg2(ClO4)24H2O phases are found, and particle size reduction is observed at the surface. Both optical and electrochemical Mott-Schottky (M–S) analysis suggest an intraband level in the electronic structure of Hg2+ modified CdS. Sulfurized CdS films, on the other hand, keep unchanged their crystalline and morphological structure, as well as optical properties. Energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and M–S analysis indicate an increase of sulfur concentration at the surface of sulfurized CdS thin films, leading to a more stoichiometric CdS compound, which used to have lower conductivity. It demonstrates that ion exchange process or cationic substitution is effective for structural and physical property modification, whereas a gaseous saturation method or anionic modification results in a notable surface energy alteration in thin solid CdS films.

Accumulation of sulfur and glutathione in leaves of woody plants growing under the conditions of outdoor air pollution by sulfur dioxide

In the course of human industrial activity, atmospheric air is polluted by gaseous pollutants, among which sulfur compounds, and sulfur dioxide (SO2) in particular, play a key role. Vegetation is a universal filter that is capable, in conjunction with certain technical facilities, of protecting the environment from pollution by the ingredients of industrial emissions. The purpose of this work is to determine the level of accumulation of sulfur and glutathione in the leaves of woody plants growing in the areas of sanitary protection zones of enterprises of the city of Zaporizhzhya in order to develop recommendations for the creation of an effective biofilter. The objects of the study were the woody plant species growing in the area of protective plantations of a number of enterprises in Zaporizhzhya: RE Zaporizhzhya Titanium &amp; Magnesium Combine, Zaporizhzhya Aluminium Plant PJSC, Zaporizhzhya Abrasive Plant PJSC, Zaporizhstal PJSC, Zaporizhzhya Ferroalloy Plant PJSC, Zaporizhvohnetryv PJSC, PrJSC "Ukrgrafit" and Zaporizhtransformator PJSC. The control area was a forest belt located 12 km away from the source of pollution. At each site 5 model trees of a given age category of each species were selected. The leaves needed in order to determine the sulfur content were taken from the south-eastern side of the crown at a distance of 2 m above the soil surface under the same lighting conditions. We have established that the accumulation of sulfur in leaves of woody plants which grow under the conditions of outdoor air pollution by sulfur dioxide (SO2) occurs during the entire vegetation period, with the young leaves that have just finished growing being the most affected. The maximum amount of sulfur is observed at the end of the growing season. The greater concentration of sulfur in the leaves of woody plants in the areas of sanitary protection zones of industrial enterprises is linked to the higher level of gaseous pollutant emissions in the atmosphere of a given enterprise, but the degree of increase in the content of the pollutant in the leaves of plants of various protective plantations is not proportional to the quantitative indicators of the level of sulfur dioxide (SO2) in the air. Woody plant species were divided into three groups according to the amount of sulfur accumulated in their leaves: І – the maximum level – Betula pendula, Tilia cordata, Salix alba, Robinia pseudoacacia, Populus alba, P. simonii, P. nigra, ІІ – medium – Acer platanoides, A. negundo, Fraxinus lanceolata, Catalpa bignonioides, ІІІ – the smallest – Morus alba, Ailanthus altissima, Elaeagnus angustifolia and Ulmus carpinifolia. The increase in sulfur content in the leaves of woody plants growing in the area of sanitary protection zones is consistent with the increase in glutathione content compared to our control parameters, which is not only of high physiological significance, but its formation can also be one of the ways of metabolizing this element. The obtained results can be used for the development of recommendations with the purpose of selecting the assortment of woody plants for the reconstruction of green plantations growing in the area of sanitary protection zones of enterprises. In a subsequent study, the accumulation of gaseous pollutants such as chlorine and phenol in the leaves of woody plants growing in and around protective forest belts will be examined.

Study of the optical properties of amorphous As–Se–S thin films

This study investigates the effects of substitution of selenium by sulfur on the optical constants of amorphous (a-)As20Se80 − xSx films (x = 0, 4, 8, 12, 16, and 20 at%), where the coordination number for both Se and S is the same. The absorption coefficient, α, and the index of refraction, n, were derived using the transmission spectra in a wide range of wavelengths from 400 to 2500 nm. This revealed that the index of refraction for the a-As20Se80 − xSx system decreases with increase in sulfur content throughout the range under study. The effective coordination number of As has been determined based on the refractive index dispersion analysis. A decreasing in Nc from 4.022 to 3.752 with increase content of sulfur from 0 to 20 at% has been recorded. In addition, the optical bandgap, Eg, of the a-As20Se80 − xSx thin films increases with increase in S content which can be explicated in terms of the chemical bond approach.

Thermal and X-ray phase analysis of the “lead-containing dust–sulfur” system

The study of phase transformations in the system” lead-containing dust – sulfur ” is actual, as in many pyrometallurgical processes lead-containing dust is formed. The accumulation of such industrial waste causes ecologically stress on the environment. The sulfur is select as a sulfiding agent due to the problem of its utilization in the oil industry. The article covers the possibility of lead dust sulfiding with technical sulphur. Thermal and x-ray phase analysis of mixtures of lead dust and elemental sulfur in various ratios was carried out. Thermal analysis was performed on a Q-1000/D derivatives without air access, which was achieved by blocking crucible with the analyzed samples by aluminum oxide, in the temperature range 20-1000 ° C, heating mode – dynamic (dT/dt = 10 deg/min), reference substance – calcined Al2O3. X-ray diffraction analysis was performed on an automated diffractometer DRON-4 with CuКa-radiation and β-filter. In the studied system, the main temperature intervals, wherein sulfur actively reveal itself, are 60-220 and 220-360 °C. The state of the system beyond 450 °C is clear from the physical properties of the lead dust. Rising of sulfur concentration increases the visibility of the peak on the DTA-curve associated with polymorphic transformation of lead oxy-sulfates and activation of sulfide formation processes. The increase in the intensity of the effects of sulfur direct interaction with the components of the charge reflects the difference in sulfur concentrations in the compared samples. On the other hand, the increase of sulfur content in the composition of the sample leads to some attenuation of the physical properties (melting) of lead oxy-sulfates. Thus, the increase of the sulfur content in the charge more strongly stimulates the development of sulfidization process in the system, which takes place within 140-300 °C. Within the same next stage of thermal manifestation, sulfide formation in the system and activation of the lead compound interaction is directly related to sulfur. The scientific and practical significance of the investigation is in the possibility of the use of technical sulfur, waste oil industry for sulfiding lead dust.