scholarly journals Impact of external physical effects on water and aqueous solutions: the problem of “memory”

2019 ◽  
Vol 59 (7) ◽  
pp. 1-16
Author(s):  
Ksenia A. Nurislamova ◽  
◽  
Alena S. Franz ◽  
Vyacheslav F. Markov ◽  
Larisa N. Maskaeva ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Electrical Conductivity ◽  
Aqueous Solutions ◽  
Solid Phase ◽  
Cluster Structure ◽  
Lead Salt ◽  
Physical Factors ◽  
Scientific Publications ◽  
Physical Effects ◽  
The Impact

A brief analysis of scientific publications on the changes in the physicochemical properties of water and aqueous solutions under the influence of temperature, magnetic and electric fields, laser and microwave radiation, ultrasound, and mechanical mixing was performed. A number of researchers have shown the influence of such effects on changes in pH and redox potential, electrical conductivity, surface tension and viscosity of an aqueous solution. The question of influence of external physical effects on water and aqueous solutions remains controversial. Some scientists suggest that water has a cluster structure, which is influenced by physical effects. An important aspect of the problem is the impact on the subsequent behavior and the final result of a chemical process involving previously treated aqueous solutions. Using water solutions of lead and thiourea as an example, the effect of their temperature prehistory in the range of 275-369 K on the kinetics of precipitation of the solid phase of lead sulfide and their microstructure is demonstrated. A threefold change in the composition of supersaturated CdxPb1–xS solid solutions precipitated from solutions containing a lead salt with different temperature prehistory was established. It is shown that the “memory” on the preliminary temperature effect is maintained for at least a day. The influence of electromagnetic treatment of water and aqueous solutions on the content of dissolved oxygen, pH and electrical conductivity is analyzed. Some scientists explain these results by the influence of the field on the structure of hydrogen bonds, others by a change in the cluster structure of water, as well as by the presence of ferromagnetic particles in water. The review presents the current state of the problem of the “memory” effect and the related influence of the prehistory of the impact of physical factors. The review suggested that the “memory” of an aqueous solution is the preservation for a certain time of the changes in its structure and properties that have arisen as a result of the effect. The basic ideas about the mechanisms of influence of the prehistory of physical effects on aqueous solutions are given.

scholarly journals Acetylacetone functionalized magnetic carbon microspheres for the highly-efficient adsorption of heavy metal ions from aqueous solutions

RSC Advances ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 3337-3344 ◽  
Author(s):  
Jie Ma ◽  
Mengya Sun ◽  
Yulan Zeng ◽  
Zhenhua Liu ◽  
Manman Zhang ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Heavy Metal ◽  
Aqueous Solutions ◽  
Metal Ions ◽  
Heavy Metal Ions ◽  
Solid Phase ◽  
Carbon Microspheres ◽  
Highly Efficient ◽  
Magnetic Carbon

Herein, Acac-C@Fe3O4, a magnetic carbon (C@Fe3O4) modified with acetylacetone (Acac), was first prepared and used as a solid-phase adsorbent for adsorbing some heavy metal ions from aqueous solution.

The electrical conductivity and other properties of sodium hydroxide in aqueous solution, as elucidating the mechanism of conduction.

1905 ◽  
Vol 74 (497-506) ◽  
pp. 280-283 ◽  
Author(s):  
William Robert Bousfield ◽  
Thomas Martin Lowry ◽  
Henry Edward Armstrong
Keyword(s):  
Aqueous Solution ◽  
Electrical Conductivity ◽  
Aqueous Solutions ◽  
Sodium Hydroxide

The original object of the research was to investigate the decay, as the temperature rises, in the “ionising” properties of water; which is manifest, especially in the case of the alkalies, in the inflected character of the curves expressing the relation between temperature and conductivity in aqueous solutions.

scholarly journals Concentric zoning patterns in crystallizing (Cd,Ca)CO3 solid solutions from aqueous solutions

1999 ◽  
Vol 63 (3) ◽  
pp. 331-343 ◽  
Author(s):  
Á. Fernández-González ◽  
M. Prieto ◽  
A. Putnis ◽  
S. López-Andrés
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Solid Solutions ◽  
Growth Process ◽  
Equilibrium Distribution ◽  
Reaction Path ◽  
Solid Phase ◽  
Equilibrium Partitioning ◽  
Compositional Zoning ◽  
Stoichiometric Proportion

AbstractOtavite-calcite solid solutions have been synthesized to investigate the factors which control the patterns of compositional zoning. The equilibrium partitioning of otavite between the aqueous and the solid phase can be described by means of a function XCdCO3(XCd,aq)eq, which relates the solid mole fraction and the aqueous activity fraction of Cd. According to this function, there is a strong preferential partitioning of Cd towards the solid. A set of experiments starting with parent solutions with different Cd2+/Ca2+ ratios was carried out. In these experiments nucleation takes place at high supersaturations and the Cd2+ and Ca2+ ions tend to be laid down in a ratio which deviates from the equilibrium distribution. Experimental nucleation data can be fitted to a curve XCdCO3(XCd,aq)ef of the same functionality as that for equilibrium.After nucleation, supersaturation decreases as the crystals grow. During this process, substituting ions are not incorporated into the solid in the same stoichiometric proportion as in the aqueous solution. Therefore, crystal and fluid compositions tend to vary as growth proceeds and this evolution is registered as a compositional zoning. The curves XCdCO3(XCd,aq)eq and XCdCO3(XCd,aq)ef confine the reaction path corresponding to the growth process. Here, these curves are used to account for the observed zoning patterns.

scholarly journals Assessment of the degree of technogenic load in the zone of influence of CHP-5 on snow cover

2019 ◽  
Vol 59 (8) ◽  
pp. 147-155
Author(s):  
Anna I. Fokina ◽  
◽  
Olim M. Abdukhalilov ◽  
Svetlana G. Skugoreva ◽  
Tamara Ya. Ashikhmina ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Solid Phase ◽  
Leeward Side ◽  
Continuous Control ◽  
The South ◽  
Carcinogenic Activity ◽  
Sulfate Ions ◽  
Snow Water ◽  
The Impact ◽  
The City

Combined heat and power plant (CHP) are sources of environmental pollution and therefore requires continuous control of the flow of pollutants which are generated during their work. One of the leading CHP in the city of Kirov (Kirov region, Russia) is a CHP-5 located in the South-Western outskirts of the city. The aim of the study was to assess the degree of anthropogenic load and the territorial focus of the impact of CHP-5 on the natural environment according to the results of chemical analysis of snow. As indicators of contamination used in the mass concentration of ions of sodium, ammonium, potassium, magnesium, calcium, strontium, zinc, cadmium, lead, copper, fluoride-, chloride-, nitrate-, phosphate- and sulfate-ions; the concentration of polycyclic aromatic hydrocarbons (PAH) in solid phase of snow water, acidity and electrical conductivity. It was found that the samples of snow water in areas near CHP-5 had a content of inorganic ions and PAHs exceeding the background values. The higher content of ions and heavy metals (HM) differed from forest sites in comparison with meadow. The highest concentrations of sodium, ammonium, potassium, calcium, magnesium ions, more alkaline reaction of the medium are determined in the snow water of the leeward areas of CHP-5. In comparison with background sites, the highest content of HM ions in snow water was found in samples from sites in the South-West direction from the CHP near the place of storage and transportation of coal. The most polluted PAHs are the areas located on the leeward side of the CHP and near the Sovietsky tract. The carcinogenic activity of PAHs in the solid phase of snow water is quite high and varies from 6.79 to 9.71 µg/dm3. Maximum electrical conductivity, high concentrations of potassium, calcium, copper, lead, zinc, chloride, nitrate, sulfate ions, increased content of pyrene relative to background, benz[b]fluoranthene, benzo[a]pyrene and benzo[g,h,i]perylene is set for the forest area (4-S-W), located in the south-western direction from the CHP, in the immediate vicinity of storage and transportation of coal. This site is the most polluted of all investigated, the degree of its pollution can be characterized as an average.

Working conditions and the formation of health risks among workers of the petrochemical industry engaged in the production of methanol and its derivatives

2019 ◽  
pp. 266-271
Author(s):  
Nina M. Meshchakova ◽  
Marina P. Dyakovich ◽  
Salim F. Shayakhmetov
Keyword(s):  
Working Conditions ◽  
Health Risks ◽  
Quantitative Assessment ◽  
Circulatory System ◽  
Medical Examination ◽  
Physical Factors ◽  
Labor Intensity ◽  
Industrial Noise ◽  
Harmful Substances ◽  
The Impact

Introduction.Methanol and its derivatives occupy one of the leading places among the main organic synthesis intermediates in terms of their importance and scale of production. According to experts, by 2027 the global demand for methanol can reach 135 million tons, the annual growth will be about 5.5%. However, there is little information regarding the assessment of working conditions and occupational risks for workers in modern methanol production and its derivatives.The aim of the studyis hygienic assessment of working conditions and the formation of health risks in workers of modern production of methanol and methylamines.Materials and methods.The assessment of the main adverse factors of production is given. When studying the state of health, objective indicators (the results of an in-depth medical examination) and subjective (the results of a quantitative assessment of the risks of the main pathological syndromes associated with health) are considered.Results.According to long-term observations, the concentration of harmful substances in the air of the working area, indicators of labor severity, parameters of physical factors met hygienic requirements, with the exception of industrial noise exceeding the maximum permissible level, as well as labor intensity of 1 degree. The General assessment of working conditions corresponds to the category of harmful 2 degrees (3.2). According to the results of the medical examination and quantitative assessment of the risks of health disorders in workers, the most significant were functional disorders and diseases of the circulatory system. The levels of somatic pathology on the part of the main body systems were significantly higher in apparatchiks compared to the engineering and technical personnel (ETP).Conclusions:In the production of methyl alcohol and methylamines, the main hygienic importance is the impact on workers of the complex of harmful substances of 1-IV hazard classes in low concentrations, increased levels of industrial noise, labor intensity of 1 degree. According to the subjective assessment of health and medical examination, the greatest prevalence of health risks in workers was observed from the circulatory system, and the levels of the revealed somatic pathology were statistically significantly higher in apparatchiks compared with the ETP.

Problems of Implementation of an Import Substitution Policy in the Oil Industry

2019 ◽  
pp. 50-57
Author(s):  
Yu. V. Vertakova ◽  
A. S. Evtyukhin
Keyword(s):  
Import Substitution ◽  
Oil Industry ◽  
Investment Climate ◽  
Scientific Publications ◽  
Stage Of Development ◽  
Current Economic Situation ◽  
Negative Effect ◽  
Substitution Policy ◽  
Investment Process ◽  
The Impact

The presented study addresses the issues of implementation of an import substitution policy in the Russian oil industry. Support of domestic production is a key objective specified in the message of the President of the Russian Federation in 2019. In light of the current economic situation and considering the importance of the oil industry for the Russian economy, an import substitution policy could help achieve the objective set by the President.Aim. The study aims to identify the problems and ways of implementation of an import substitution policy in the Russian oil industry.Tasks. The authors analyze scientific publications on import substitution and the state of the Russian oil industry at the current stage of development; determine the directions and fundamental trends in the development of the oil industry; identify obstacles that hinder the implementation of an import substitution policy in the oil industry; describe conditions that facilitate the development of the  investment process in the oil industry; propose comprehensive methods and ways to intensify investments and optimize costs for enterprises in the oil industry.Methods. This study uses general scientific methods of cognition, comparative and statistical analysis to identify problems in the implementation of an import substitution policy in the oil industry.Results. Examination of the current state and development prospects of the oil industry allows the authors to identify obstacles to the development of import substitution. The study shows their impact on the potential of import substitution, which has a negative effect on the prospects of intensification of investment processes, and proposes comprehensive methods and mechanisms that could neutralize the impact of the identified obstacles, thus facilitating the formation of a positive investment climate. Conclusions. Investment climate is shown to have a decisive impact on the potential of import substitution in the Russian oil industry, and ways of overcoming negative trends in the development of the oil industry are proposed.

Development of Strategies for Glycopeptide Synthesis: An Overview on the Glycosidic Linkage

2020 ◽  
Vol 24 (21) ◽  
pp. 2475-2497
Author(s):  
Andrea Verónica Rodríguez-Mayor ◽  
German Jesid Peralta-Camacho ◽  
Karen Johanna Cárdenas-Martínez ◽  
Javier Eduardo García-Castañeda
Keyword(s):  
Chemical Synthesis ◽  
Solid Phase ◽  
Building Blocks ◽  
Heterogeneous Environments ◽  
Phase Synthesis ◽  
Low Concentrations ◽  
Biological Sources ◽  
Synthetic Routes ◽  
The Impact ◽  
Potential Use

Glycoproteins and glycopeptides are an interesting focus of research, because of their potential use as therapeutic agents, since they are related to carbohydrate-carbohydrate, carbohydrate-protein, and carbohydrate-lipid interactions, which are commonly involved in biological processes. It has been established that natural glycoconjugates could be an important source of templates for the design and development of molecules with therapeutic applications. However, isolating large quantities of glycoconjugates from biological sources with the required purity is extremely complex, because these molecules are found in heterogeneous environments and in very low concentrations. As an alternative to solving this problem, the chemical synthesis of glycoconjugates has been developed. In this context, several methods for the synthesis of glycopeptides in solution and/or solid-phase have been reported. In most of these methods, glycosylated amino acid derivatives are used as building blocks for both solution and solid-phase synthesis. The synthetic viability of glycoconjugates is a critical parameter for allowing their use as drugs to mitigate the impact of microbial resistance and/or cancer. However, the chemical synthesis of glycoconjugates is a challenge, because these molecules possess multiple reaction sites and have a very specific stereochemistry. Therefore, it is necessary to design and implement synthetic routes, which may involve various protection schemes but can be stereoselective, environmentally friendly, and high-yielding. This review focuses on glycopeptide synthesis by recapitulating the progress made over the last 15 years.

Application of Silica Nanoparticles in the Determination of Herbicides in Environmental Water Samples Using Liquid Chromatography-Mass Spectroscopy

2020 ◽  
Vol 16 (5) ◽  
pp. 748-756
Author(s):  
Mir Waqas Alam ◽  
Tentu Nageswara Rao ◽  
Yarasani Prashanthi ◽  
Vourse Sridhar ◽  
Adil Alshoaibi ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Liquid Chromatography ◽  
Silica Nanoparticles ◽  
Solid Phase ◽  
Silica Nanoparticle ◽  
Environmental Water ◽  
Phase Extraction ◽  
Functionalized Nanoparticles ◽  
Supporting Material

Background: Herbicides are very beneficial in the crop yield with the aid of controlling weeds within the agriculture, but several herbicides are chronic in soil. Objective: In this study, nanoparticles and the packages of synthesized novel silica nanoparticles were studied for the preconcentration of herbicides. Methods: These nanoparticles prepared by the Stöber mechanism were purified and functionalized. Nanoparticles thus prepared successfully were used as supporting material for the preconcentration of residues of herbicides in the water. Results: Preconcentration was achieved by preparing the silica-based solid-phase-extraction cartridges. Nanoparticles used for this purpose were within the range of 50-250 nm. An SPE cartridge was prepared by packing 200 mg of silica nanoparticle in the empty cartridge of diameter 5.5 cm and length 0.6 cm in between PTFE frits. Aqueous solutions of 0.1 μg/ml of herbicides were prepared separately, and 10 ml of the solution was passed through the cartridge at the rate of 0.2 ml/min. After passing 10 ml volume of the aqueous solution, residues adsorbed on the cartridge were eluted using 2 ml of acetonitrile. The eluate was injected to determine the herbicide residue adsorbed on the SPE cartridge. Conclusion: In the study, it was found that greater than 90% of the herbicide residues were trapped on silica nanoparticle-based SPE cartridge. An analytical method was developed for the simultaneous determination of these herbicides. The residues were quantified by LC-MS/MS with ESI mode.

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