Physical And Chemical Properties Of Lead Pdf
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Allotropes Some elements exist in several different structural forms, called allotropes. Each allotrope has different physical properties. For more information on the Visual Elements image see the Uses and properties section below.
- 3.5: Differences in Matter- Physical and Chemical Properties
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- Zinc, Physical and Chemical Properties
3.5: Differences in Matter- Physical and Chemical Properties
The paper presents the results of studies of bottom sediments taken from the southern part of the Bratsk Reservoir. The following analyses have been conducted: trace element analysis, particle-size analysis as well as chemical analysis of water, hydrochloric acid and alkaline extracts for 18 samples of the bottom sediments.
The granulometric analysis has identified the predominance of fine silt and silty-clayed sediments. The data on the content of trace elements in the bottom sediments of the Bratsk Reservoir is presented in comparison with their content in the natural environment of the Baikal region; the anomaly ratio was used to characterize the excess for trace elements.
In this research, an attempt was made by using a correlation analysis to evaluate the impact of various physical and chemical characteristics of the bottom sediments, such as the content of clay fraction, organic carbon, carbonates, and water-soluble salts on the accumulation of trace elements. The ecological state of the entire reservoir geosystem, as well as its individual components water mass, bio-organisms, aquatic vegetation, sediments bottom deposits , depends on a number of natural and anthropogenic factors.
As a result of contamination, the trace element content in all components of the geosystem can vary considerably 1 , 2 , 3 , 4 , 5. A dangerous trend in this case is the accumulation of toxic elements, such as heavy metals 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , The accumulation of trace elements in bottom sediments occurs along with complex physical and chemical mechanisms of absorption, which depend on the peculiarities of the composition, structure and properties of the sediment, as well as on the properties of the absorbed compounds 20 , The accumulation might occur through interaction with the solid phase, following the mechanisms of ion exchange and complex formation with humic acids, adsorption by clay and other minerals, iron and manganese hydroxides, etc.
Therefore, the accumulation and distribution of trace elements is greatly influenced by different physical and chemical characteristics of the sediment, such as granulometric composition particle-size distribution , particularly the content of silt clay fraction, the content of organic carbon, carbonates, water-soluble salts, and amorphous oxides It is known that these components are involved in the formation of structural bonds of dispersive soils and, depending on the composition and amount, are able to weaken or strengthen these bonds, thus affecting the deformation and strength properties These components also have a significant effect on the physical and chemical activity of the sediments.
For example, elevated concentrations of organic carbon lead to a decrease in the content of inorganic carbon and hydrogen index and, as a consequence, to the change of oxidation-reduction potential, leading to the release of metals from the sediments into the aquatic environment Due to the leaching of water-soluble compounds, the density of the texture of subsoils, their cohesive properties and permeability change.
In the process of dissolution and leaching of salts, the composition of absorbed cations, which significantly affect the properties of sediments, may change The purpose of this study, based on the results of laboratory analyses of sediments taken from the south of the Bratsk Reservoir, is to identify possible existing relationship between such physical and chemical characteristics of the bottom sediments as the content of clay fraction, organic carbon, carbonates, water-soluble salts, amorphous oxides and accumulation of trace elements.
The body of water is located in the south of the Central Siberian Plateau and is elongated in meridional direction, from south to north, covering the steppe, forest-steppe and taiga landscape-climatic zones.
Most accumulative river terraces have the common gently-sloping surface leveled out by denudation some terraces were flooded after creation of the Bratsk Reservoir This reservoir is used mostly for energy purpose, which does not preclude its use for other purposes, such as for water supply, recreation, fisheries, water transport and timber floating.
The Bratsk Reservoir has been operating for almost 50 years, since The present exploration target is the southern part of the Bratsk Reservoir — from the transient region to the mouth of the Unginsk Creek. The width of the reservoir at the site under study varies from 1 to 7. This is the most developed part of the reservoir.
There are several small towns on the shores with existing industries Usolye-Sibirskoye — chemical industry, mechanical engineering; Svirsk — timber and woodworking industry; Cheremkhovo — coal-mining, timber and woodworking industry and a large number of villages with well-developed agriculture 30 Fig.
The territory belongs to the forest-steppe zone strongly affected by gully erosion Layout of the study area: 1 — settlements; 2 — agricultural land: arable land, pastures, 3 — sediment sampling points with sample numbers.
The rivers flowing into the reservoir on the site under study the Irkut, Kitoi, Belaya, Ushakovka, Kuda, Osa are of secondary importance here. The bedrock is Lower-Middle-Cambrian rock, consisting of dolomites, limestones, gypsum, anhydrite and carbonate breccias and Middle-Upper-Cambrian rock, which consist of marl, dolomite, argillites and aleurolite intercalations with thin gypsum lenses.
The alluvial deposits are represented by sands — from fine- to medium-grained, with interbedded clay and loam, fine sandy loams, loams and gravels. The slopes and alluvium of river terraces are covered with deluvial talus clay loam and fine sandy loam of small thickness — 10—15 m Sediment samples were collected from 15 different locations of Bratsk Reservoir in and using a sediment core sampler operated from a boat.
The sampler was submerged on a steel line using a hand-operated winch. Sampling depth varied from 2. The selected samples were dried to air-dry state in vitro , and then each sample was divided into 2 parts.
This leach is partial for magnetite, chromite, barite and other spinels and potentially massive sulphides. The other trace element contents were determined using the INAA instrumental neutron activation analysis method.
After a 7-day decay to allow Na to decay the samples are counted on a high purity Ge detector with resolution of better than 1. Analysis results are given in ppm 34 , Another part of each sample was analyzed in the Analytical Centre of the Institute of the Earth Crust Irkutsk, Russia using a special method developed for analysing clay and loessial soils Clay and loess deposits are complex natural formations consisting of the primary particles and aggregates. The presence of aggregates affects the results of particle size granulometric analysis, as it reduces the content of fine particles and increases the content of coarse ones.
This distorts the correct understanding of the massive material, the content of certain particles in it and its classification. The particle size analysis shows the limiting extreme dispersion, but in order to obtain information about the natural dispersion, it is necessary to know the number of secondary micro-aggregate particles.
This method allows obtaining such information without isolating the micro-aggregate composition or performing additional micro-aggregate analysis of the soil. Namely, the granulometric analysis was made by pipette method, using 3 processes of specimen preparation 35 : 1 aggregate process shaking up of the specimen in water causes the destruction of coarse water-unstable aggregates ; 2 the semi-disperse process boiling of triturated specimen in presence of ammonia , and 3 disperse preparation boiling of triturated specimen with sodium pyrophosphate leads to maximum destruction of aggregates.
The semi-dispersed technique is a standard one and it is recommended for determining the particle size distribution of clay soils and for naming the sample within the framework of the classification. By water, muriatic and alkaline extracts the components and structural bonds such as water soluble salts, carbonates, amorphous sesqui-oxides and mobile Al 2 O 3 forms were determined.
To a certain extent, water extract imitates the material composition of the soil solution, so it can help get an insight into the content and composition of the most mobile soil components that are more capable of migration.
At the same time, the dissolution of readily-soluble salts occurs, while medium- and low-soluble salts are partially dissolve. Analysis of the extract begins with determining the carbonate and total alkalinity, as well as the pH of the extract, then the amount of dry residue is determined the content of water-soluble salts is determined as the sum of anions and cations after evaporation in a water bath.
Then, using special coefficients, oxides are recalculated for the content of carbonate salts CaCO 3 , MgCO 3 , FeCO 3 and their sum is determined, which characterizes the total carbonate content of the soil.
Analysis of the alkaline extract allows us to determine the content of mobile Al 2 O 3 forms 25 , The humus content was determined according to I. The oxidation occurs in a highly acidic medium and is accompanied by the reduction of hexavalent chromium to the trivalent.
Based on the difference of potassium bichromate — before and after oxidation — the content of organic carbon in the soil is found The material composition of the bottom sediments at the site under study refers to the terrigenous genetic type.
The terrigene sediments are formed from detrital or pelitic lutaceous material, originating from the banks, due to various exogenous processes As a result of mechanical differentiation under the action of waves, currents, underwater gravitational processes, etc. With distance from the shoreline, they are replaced by fine sands and silts. The granulometric analysis of the sediments from the south of the Bratsk Reservoir has determioned the predominance of fine silt and silty-clayed muds.
The sediment received its name according to the particle-size distribution of the sample with semi-dispersed preparation. The particle-size distribution of each sample is presented in two versions of sample preparation: a — semi-disperse, and b — dispersed ones. The graphs demonstrate how the ratio of particle contents by fractions significantly changes towards the increased number of more micro-fine particles with maximum destruction of aggregates in the case of dispersed sample preparation.
The particle contents in the Bratsk Reservoir sediment samples: A — semi-dispersed specimen preparation, B — dispersed specimen preparation. In fine silt muds, the content of 0. The fractions of 0. As a rule, environmental assessment of the levels of content of chemical elements in the natural environments is carried out by comparing their actual concentrations versus regulatory standardized parameters.
However, to date there are no regulatory requirements for the maximum permissible trace element concentration for the sediments in Russia. It may be noted that the average trace element contents in the deep abyssal silt of Lake Baikal for the most part can be checked against the maximum contents in the bottom sediments of the Bratsk Reservoir or exceed them.
Thus, in order to determine the excesses of the aforementioned trace elements Co, Cr, Cu, Mn, Ni, Pb, Th, V, Zn , anomaly ratio AR was used, which is calculated as the ratio of the content of a chemical element in the studied natural object to the geochemical background So, the highest excess of the background among the aforementioned is recorded for Co, Ni and Zn AR is 2.
The average content of other elements exceeds the geochemical background less than 1. The salinity quality is predominantly of carbonate-sulfate type; it is caused by a high degree of water solubility of the chloride salts, which practically do not accumulate in the sediments. The total content of carbonates in the sediments varies widely, from According to Ryashchenko 38 , the constant presence of CaCO 3 dominated carbonates is a regional feature of quaternary sediments loessial and clayey soils in the south of Eastern Siberia, as well as salinity, however, at a weaker level S ws varies within 0.
The humus content ranges within 1. Based on the studies by Butakov 44 , it was determined that the bulk organic carbon in the sediments of the Bratsk Reservoir accounts for humic acid.
This indicates a high degree of humification of the reservoir bottom sediments, which, in turn, suggests the allochthonous nature of the humic substance in the reservoir sediments.
Many studies have confirmed that particle-size distribution of sediments affects the transport and accumulation of high-density heavy metals in soils 45 , Huang et al.
In this study, the correlation analysis has also showed that the highest value in the accumulation of trace elements in the sediments is their dispersion, i. Co, Cr, Cu, Ni, Pb and Zn demonstrated the most significant positive correlation in terms of the content of pelitic clayey particles in an aggregated state r ranges from 0.
When semi-dispersed and dispersed sample preparation is used, i. Thus, when semi-dispersed and dispersed sample preparation is used, only Co, Ni and Pb show the average degree of correlation 0. The influence of organic matter on the accumulation of heavy metals in the sediments is insignificant. The weak correlation between concentrations of heavy metals in the sediments containing organic matter in most cases suggests the secondary role of humic substance in the process of accumulation and migration of metals, and it is the evidence of predominantly terrigenous nature of the formation of trace-element composition of the bottom sediments in the Bratsk Reservoir.
The territory under study is intensively used for agricultural purposes. Farms tend to use large quantity of fertilizers both mineral and organic ones and pesticides to promote the acceleration of agricultural production. As numerous studies show, this practice often leads to the accumulation of trace such elements as Cr, Ni, Cu, Zn, As, Cd and Pb in soils 45 , 48 , Soil erosion, being an important factor in the redistribution of soil in the reservoir, is probably the main mechanism by which the studied trace elements enter the bottom sediments of the reservoir Besides, there is a moderate negative correlation between the content of water soluble salts and S ws and the content of Mn, Pb and V in the bottom sediments.
Interestingly, metals are correlated with each other. Such a pronounced correlation might indicate that these trace elements have the same source of influent into the reservoir For Th and V, the correlation with other trace elements mainly varies from very low to moderate.
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Lead is a chemical element with the symbol Pb from the Latin plumbum and atomic number It is a heavy metal that is denser than most common materials. Lead is soft and malleable , and also has a relatively low melting point. When freshly cut, lead is silvery with a hint of blue; it tarnishes to a dull gray color when exposed to air. Lead has the highest atomic number of any stable element and three of its isotopes are endpoints of major nuclear decay chains of heavier elements. Lead is a relatively unreactive post-transition metal.
It delivers electricity and clean water into our homes and cities and makes an important contribution to sustainable development. More than that, it is essential for life itself. The following describes different properties of copper, divided by type chemical, mechanical and physical. All common metals and alloys react with a moist atmosphere and corrode. However, due to the chemical properties of copper, the corrosion process is very slow. The corrosion resistance of copper and copper alloys is based on their ability to form stable compounds that provide some protection from corrosive attack.
Lead is a bluish-white lustrous metal. It is very soft, highly malleable, ductile, and a relatively poor conductor of electricity. It is very resistant to corrosion but tarnishes upon exposure to air. Lead isotopes are the end products of each of the three series of naturally occurring radioactive elements. Lead pipes bearing the insignia of Roman emperors, used as drains from the baths, are still in service. Alloys include pewter and solder.
Zinc, Physical and Chemical Properties
It was found that main factors impeding the development of vegetation are excessive contents of Zn, Pb, and Cd, as well as eolian erosion and deficiency of macroelements. The results of biological fertilisation tests were discussed in particular with regard to the deficiency of macroelements and the immobilisation of Zn, Pb, and Cd. Pot and field experiments permitted determination of this kind of interaction with doses of mineral fertilization ensuring plant growth. Plants were introduced to the sediment without a layer of insulation.
An element is the simplest form of matter that cannot be split into simpler substances or built from simpler substances by any ordinary chemical or physical method. There are elements known to us, out of which 92 are naturally occurring, while the rest have been prepared artificially. Elements are further classified into metals, non-metals, and metalloids based on their properties, which are correlated with their placement in the periodic table. With the exception of hydrogen, all elements that form positive ions by losing electrons during chemical reactions are called metals. Thus metals are electropositive elements with relatively low ionization energies.
All matter has physical and chemical properties. Physical properties are characteristics that scientists can measure without changing the composition of the sample under study, such as mass, color, and volume the amount of space occupied by a sample. Chemical properties describe the characteristic ability of a substance to react to form new substances; they include its flammability and susceptibility to corrosion.
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