scholarly journals DEVELOPMENT OF RATIONAL METHOD OF SYNTHESIS OF NANOCRYSTALLINE LEAD MOLYBDATE IN MELTS OF Na2MO2O7 - PbCO3 SYSTEM

2017 ◽  
Vol 60 (7) ◽  
pp. 78
Author(s):  
Ghazali K. Shurdumov ◽  
Zaur A. Сherkesov ◽  
Eleоnora F. Kаndurova
Keyword(s):  
Sodium Molybdate ◽  
Carbon Oxide ◽  
Rational Method ◽  
Synthesis Process ◽  
Distilled Water ◽  
Nanocrystalline State ◽  
Lead Carbonate ◽  
Constant Weight ◽  
High Productivity ◽  
Lead Molybdate

The work presents material on interaction of dimolybdate of sodium and carbonate of lead, and also data on the development of a rational method for the synthesis of PbMoO4 in the melts, characterized by high productivity and yield of the target product of "h.с." brand in the nanocrystalline state. To achieve the work aims the thermodynamic assessment of the ability of the synthesis of molybdate of lead in melts of the system Na2Mo2O7 – PbCO3 was given. It is shown that the thermodynamic probability of formation of molybdate of lead in a number of Na2Mo2O7 – PbO(PbO2, PbCO3), is maximal for the process in the system of dimolybdate sodium – lead carbonate. The starting material for the synthesis of lead molybdate – dimolybdate sodium – was synthesized from recrystallized and dehydrated sodium molybdate and molybdenum oxide (VI). The melting temperature of synthesized dimolybdate sodium is 612 °C (614 °C – literature data). Synthesis of lead molybdate was done after careful grinding of the initial reagents and sifting through a sieve. The temperature of the synthesis process of 650 °C was maintained for 1.5 h until reaching the constant weight of mixture. Then mixture was sintered, cooled to room temperature and leached with hot (70-80 °C) distilled water. The precipitate of lead molybdate was filtered, washed on the filter to a negative reaction on molybdate ion. Synthesized molybdate of lead was dried, washed and calcined to constant weight. The yield of lead (II) molybdate was of 99.88% of the theoretical. Analysis of the obtained product was based on reaction between PbMoO4 with sodium carbonate with the formation of sodium molybdate, lead oxide (II) and carbon oxide (IV). Thus obtained sample was sintered, leached with hot distilled water and filtered. The residue was treated with acetic acid obtained from acetate of lead, the latter is determined in a form of lead molybdate (sodium molybdate deposition). To determine molybdenum from the filtrate from PbO, the inverse sedimentation method was used, in the form of BaMoO4, which is its weight form. The work also contains a material on the identification of the synthesized product by modern research methods.For citation:Shurdumov G.K., Cherkesov Z.A., Kandurova E.F. Development of rational method of synthesis of nanocrystalline lead molybdate in melts of Na2Mo2O7 – PbCO3 system. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 7. P. 78-84.

The Properties of Rubber Prepared from Dialyzed Latex

1939 ◽  
Vol 12 (4) ◽  
pp. 695-705
Author(s):  
H. P. Stevens ◽  
J. W. Rowe
Keyword(s):  
Acetic Acid ◽  
Hevea Brasiliensis ◽  
Aqueous Ammonia ◽  
Regenerated Cellulose ◽  
Distilled Water ◽  
Washing Machine ◽  
Rubber Content ◽  
Constant Weight ◽  
No Formation ◽  
Before And After

Abstract Rubber articles are prepared from ammonia-preserved latex by two principal processes, viz., evaporation or coagulation, or by a combination of both. The object of this work was to determine what advantages are to be obtained by the use of a latex purified by dialysis. An 8-gallon batch of normal ammoniapreserved latex (from Hevea brasiliensis) was available and all the rubbers were prepared from this batch unless otherwise stated. The latex was kept for several days and decanted from the sludge which settles out. After straining, it was stored in one-gallon cans until required for use. Some of the latex was dialyzed through membranes of regenerated cellulose in the apparatus previously described by the authors. Some aqueous ammonia was added to the latex daily to preserve stability, and three charges of distilled water were used to complete the purification. A pressure was applied to the latex and adjusted to allow slight dilution so that there was no formation of paste on the membranes. The latex was analyzed, before and after dialysis, for total solids and dry rubber content. The former were determined by evaporating a weighed portion of the latex to constant weight at 70°. The dry rubber content was determined by coagulating the latex with about an equal volume of 1% acetic acid, crepeing the coagulum on a washing machine, and drying the crepe at, 70°

scholarly journals Repellency Effect of Prepared Neem Tree Leaves Smoke against Mosquito

2020 ◽  
pp. 1-6
Author(s):  
M. M. Jibrin ◽  
A. D. Mohammed
Keyword(s):  
Adverse Effect ◽  
Rating Scale ◽  
Distilled Water ◽  
Tree Leaves ◽  
Neem Tree ◽  
Constant Weight ◽  
Prepared Sample ◽  
Time Of Application ◽  
Neem Leaves ◽  
Before And After

The study was design to evaluate the smoke repellency effect of prepared neem leaves, against mosquito. The dried neem powder was used for making the insecticide, 10 g of powdered leaves sample was weight into a 200 ml beaker, and 5.0 g of starch was weight and added to the leave sample in the beaker. The mixture was stirred and 5.0 ml of distilled water was added gradually to the mixture in little quantity while stirring. The beaker with wet insecticide mixture was dried in an oven until a constant weight was obtained. The prepared neem insecticide was distributed among the households to use at night, to substitute synthetic insecticides. The users were randomly selected within the study area. The data was collected based on the time of application, number of bites receive before and after the application this was done based on 0-5 rating scale. The result revealed that the prepared insecticide is 100% effective though the effectiveness is dependent to time taken after application. The questionnaire was also used to assess the view of the users on the adverse effect they experienced upon the exposure to neem tree leaves prepared sample. The study has been concluded that neem leaves smoke is effective in repelling mosquito, and it can be an alternative to the synthetic insecticides hence it is safe for the users and the environment.

scholarly journals Influence of different anionic charges in lead compounds in the remediation of lead by Eleusine indica (Gaertn)

2021 ◽  
Author(s):  
Ruth Ehiarinmwian ◽  
Gloria Omorowa OMOREGIE ◽  
Beckley Ikhajiagbe
Keyword(s):  
Lead Nitrate ◽  
Polluted Soil ◽  
Soil Samples ◽  
Lead Chloride ◽  
Microbial Count ◽  
Lead Carbonate ◽  
Constant Weight ◽  
Lead Sulphate ◽  
Eleusine Indica ◽  
High Efficient

The study was carried out to investigate the remediative capacity of Eleusine indica in lead-polluted soil. Soil samples were collected near student hostel (hall 5) in the University of Benin. The soil samples were sun dried to constant weight and was pulverized with wooden roller and sieved with a hand sieve of 2 mm mesh size. The sieved soil was spiked with 0.625 g lead nitrate (PbNO3), lead sulphate (PbSO4), lead carbonate (PbCO3), lead acetetrahydrate (PbC2H6) and lead chloride (PbCl2) separately in three replicate using aqueous standard solutions. Tillers of Eleusine Indica were placed in the metal polluted soil immediately and the experiment was allowed to stay for 15 weeks. The result showed that the uptake efficiency for Eleusine indica in both shoots and roots for lead nitrate was 0.016% and 0.8%, lead sulphate 0.016 % and 0.352 %, lead carbonate 0.064% and 0.496 %, lead acetetrahydrate 0.032 % and 0.688 %, and lead chloride 0.08 % and 0.72 % respectively, indicating that the plant might have sequestered the metal in the soil rather than accumulating it in the leaves. This was evident in the presentation of the metal sequestration factor of over 70 % irrespective of the nature of the metal. Microbial count of soil before and after contamination with lead nitrate was 19000 and 4000 cfu/g indicating a reduction. The study therefore revealed that Eleusine indica is a high efficient plant in sequestering lead in polluted soil.

Microstructure and formation mechanism of combustion-synthesized rodlike Ca α-sialon crystals

2001 ◽  
Vol 16 (7) ◽  
pp. 1928-1934 ◽  
Author(s):  
Kexin Chen ◽  
Haibo Jin ◽  
M. Oliveira ◽  
Heping Zhou ◽  
J. M. F. Ferreira
Keyword(s):  
Reaction Mechanism ◽  
Combustion Synthesis ◽  
Formation Mechanism ◽  
Particle Morphology ◽  
Morphological Features ◽  
Combustion Reaction ◽  
Synthesis Process ◽  
Two Dimensional ◽  
High Productivity ◽  
The Relationship

The fabrication of rodlike Ca α-sialon crystals through a combustion synthesis process is reported in this paper. The main morphological features in the product included rodlike crystals, two dimensional elongated platelets, and equiaxed particles. By proper adjustment of the combustion parameters, a high productivity of rodlike Ca α-sialon crystals in the final product could be achieved. The combustion reaction mechanism and the relationship between the combustion parameters and the particle morphology were investigated.

Synthesis of Li[Ni0.8Co0.1Mn0.1]O2 Hierarchical Architectures and their Electrochemical Properties as Positive Materials of Li-Ion Batteries

2012 ◽  
Vol 512-515 ◽  
pp. 2028-2031 ◽  
Author(s):  
Shao Li ◽  
Li Wei Mi ◽  
Juan Juan Zhao ◽  
Chang Chun Yang ◽  
Jian Min Zhang ◽  
...  
Keyword(s):  
Electrochemical Properties ◽  
Cathode Materials ◽  
Lithium Ion ◽  
Synthesis Process ◽  
Distilled Water ◽  
Li Ion Batteries ◽  
Hierarchical Architectures ◽  
Li Ion ◽  
Synthesized Materials ◽  
Positive Materials

A series of Li[Ni0.8Co0.1Mn0.1]O2were synthesized with different [Ni0.8Co0.1Mn0.1](OH)2as precursors. Because the precursors were obtained via hydrothermal method at solutions with different ratios of ethanol and distilled water, they present different morphology in details. This phenomenon were inherited by the Li[Ni0.8Co0.1Mn0.1]O2. In addition, as-synthesized materials Li[Ni0.8Co0.1Mn0.1]O2perform distinct electrochemical properties as cathode materials in lithium-ion battery. The results indicate that more ethanol used in this work is effective to modify the surface structure of materials leading to better electrochemical properties. In addition, more ethanol in synthesis process could also improve the density of samples.

Biophysical Measurement of Molecular Weight of Foot-and-Mouth Disease RNA Fragments

1974 ◽  
Vol 32 ◽  
pp. 262-263
Author(s):  
Sydney S. Breese ◽  
Howard L. Bachrach
Keyword(s):  
Chemical Properties ◽  
Foot And Mouth Disease ◽  
Mouth Disease ◽  
Distilled Water ◽  
Bovine Plasma ◽  
Mouth Disease Virus ◽  
Foot And Mouth ◽  
Carbon Coated ◽  
Rna Fragments ◽  
Physical And Chemical

Continuing studies on the physical and chemical properties of foot-and-mouth disease virus (FMDV) have included electron microscopy of RNA strands released when highly purified virus (1) was dialyzed against demlneralized distilled water. The RNA strands were dried on formvar-carbon coated electron microscope screens pretreated with 0.1% bovine plasma albumin in distilled water. At this low salt concentration the RNA strands were extended and were stained with 1% phosphotungstic acid. Random dispersions of strands were recorded on electron micrographs, enlarged to 30,000 or 40,000 X and the lengths measured with a map-measuring wheel. Figure 1 is a typical micrograph and Fig. 2 shows the distributions of strand lengths for the three major types of FMDV (A119 of 6/9/72; C3-Rezende of 1/5/73; and O1-Brugge of 8/24/73.

Freeze-fracture, freeze-etch complementary pairs of virus-infected cells reveal value of etching even when relatively high concentrations of cryoprotectants are used

1978 ◽  
Vol 36 (2) ◽  
pp. 136-137
Author(s):  
Russell L. Steere ◽  
Eric F. Erbe
Keyword(s):  
Plant Tissue ◽  
Phosphate Buffer ◽  
Infected Plant ◽  
Freeze Fracture ◽  
Distilled Water ◽  
Virus Infected Plant ◽  
Infected Cells ◽  
High Concentrations

It has been assumed by many involved in freeze-etch or freeze-fracture studies that it would be useless to etch specimens which were cryoprotected by more than 15% glycerol. We presumed that the amount of cryoprotective material exposed at the surface would serve as a contaminating layer and prevent the visualization of fine details. Recent unexpected freeze-etch results indicated that it would be useful to compare complementary replicas in which one-half of the frozen-fractured specimen would be shadowed and replicated immediately after fracturing whereas the complement would be etched at -98°C for 1 to 10 minutes before being shadowed and replicated.Standard complementary replica holders (Steere, 1973) with hinges removed were used for this study. Specimens consisting of unfixed virus-infected plant tissue infiltrated with 0.05 M phosphate buffer or distilled water were used without cryoprotectant. Some were permitted to settle through gradients to the desired concentrations of different cryoprotectants.

Comparison of Acrylamide and Agar Gels by Freeze-Etching

1977 ◽  
Vol 35 ◽  
pp. 606-607
Author(s):  
Russell L. Steere ◽  
Eric F. Erbe
Keyword(s):  
Electron Microscope ◽  
Sodium Hydroxide ◽  
Sodium Hypochlorite ◽  
Chromic Acid ◽  
Distilled Water ◽  
Thin Sheets ◽  
Acid Cleaning ◽  
Agar Gels ◽  
Freeze Etching ◽  
Water Cut

Thin sheets of acrylamide and agar gels of different concentrations were prepared and washed in distilled water, cut into pieces of appropriate size to fit into complementary freeze-etch specimen holders (1) and rapidly frozen. Freeze-etching was accomplished in a modified Denton DFE-2 freeze-etch unit on a DV-503 vacuum evaporator.* All samples were etched for 10 min. at -98°C then re-cooled to -150°C for deposition of Pt-C shadow- and C replica-films. Acrylamide gels were dissolved in Chlorox (5.251 sodium hypochlorite) containing 101 sodium hydroxide, whereas agar gels dissolved rapidly in the commonly used chromic acid cleaning solutions. Replicas were picked up on grids with thin Foimvar support films and stereo electron micrographs were obtained with a JEM-100 B electron microscope equipped with a 60° goniometer stage.Characteristic differences between gels of different concentrations (Figs. 1 and 2) were sufficiently pronounced to convince us that the structures observed are real and not the result of freezing artifacts.

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