scholarly journals Recent Progress on the Production of Aluminum Oxide (Al2O3) Nanoparticles: A Review

2021 ◽  
Vol 1 (2) ◽  
pp. 54-77
Author(s):  
Adzra Zahra Ziva ◽  
Yuni Kartika Suryana ◽  
Yusrianti Sabrina Kurniadianti ◽  
Asep Bayu Dani Nandiyanto ◽  
Tedi Kurniawan
Keyword(s):  
Aluminum Oxide ◽  
Recent Progress ◽  
Raw Materials ◽  
Sol Gel ◽  
High Thermal Stability ◽  
Synthesis Methods ◽  
Al2o3 Nanoparticles ◽  
Advantages And Disadvantages ◽  
Wet Chemical ◽  
And Control

This study aims at discussing several methods to produce aluminum oxide (Al2O3) synthesis methods along with the advantages and disadvantages of each method used. In general, several methods are available: (1) precipitation, (2) combustion, (3) sol-gel, (4) wet chemical, (5) synthesis in supercritical water conditions, (6) microwave, (7) mechanochemical, and (8) hydrolysis, and the most efficient method for synthesizing Al2O3 is precipitation because it is facile and the simplest method (compared to other methods), can be proceeded using inexpensive raw materials, produces less pollution, and has several advantages: high purity product, high thermal stability, nearly homogeneous nanoparticle in size, and control desired particle size. The results of the study help to provide comparisons in producing various Al2O3 synthesis methods.

scholarly journals Mullite-Based Ceramics from Mining Waste: A Review

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 332
Author(s):  
Maximina Romero ◽  
Isabel Padilla ◽  
Manuel Contreras ◽  
Aurora López-Delgado
Keyword(s):  
Raw Materials ◽  
Protective Coatings ◽  
Sol Gel ◽  
Glass Ceramics ◽  
Ceramic Materials ◽  
Economic Benefits ◽  
Mining Waste ◽  
Environmental Benefits ◽  
Synthesis Methods ◽  
Over Exploitation

Mullite (3Al2O3·2SiO2) is an aluminosilicate characterized by excellent physical properties, which makes it an important ceramic material. In this way, ceramics based on mullite find applications in different technological fields as refractory material (metallurgy, glass, ceramics, etc.), matrix in composite materials for high temperature applications, substrate in multilayer packaging, protective coatings, components of turbine engines, windows transparent to infrared radiation, etc. However, mullite is scarce in nature so it has to be manufactured through different synthesis methods, such as sintering, melting-crystallization or through a sol-gel route. Commonly, mullite is fabricated from pure technical grade raw materials, making the manufacturing process expensive. An alternative to lowering the cost is the use of mining waste as silica (SiO2) and alumina (Al2O3) feedstock, which are the necessary chemical compounds required to manufacture mullite ceramics. In addition to the economic benefits, the use of mining waste brings out environmental benefits as it prevents the over-exploitation of natural resources and reduces the volume of mining waste that needs to be managed. This article reviews the scientific studies carried out in order to use waste (steriles and tailings) generated in mining activities for the manufacture of clay-based ceramic materials containing mullite as a main crystalline phase.

scholarly journals Recent Advances in Synthesis and Applications of MFe2O4 (M = Co, Cu, Mn, Ni, Zn) Nanoparticles

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1560
Author(s):  
Thomas Dippong ◽  
Erika Andrea Levei ◽  
Oana Cadar
Keyword(s):  
Antimicrobial Agents ◽  
Sol Gel ◽  
Dielectric Materials ◽  
High Coercivity ◽  
Synthesis Methods ◽  
Advantages And Disadvantages ◽  
Wide Range ◽  
Potential Applications ◽  
Co Precipitation ◽  
Zn Nanoparticles

In the last decade, research on the synthesis and characterization of nanosized ferrites has highly increased and a wide range of new applications for these materials have been identified. The ability to tailor the structure, chemical, optical, magnetic, and electrical properties of ferrites by selecting the synthesis parameters further enhanced their widespread use. The paper reviews the synthesis methods and applications of MFe2O4 (M = Co, Cu, Mn, Ni, Zn) nanoparticles, with emphasis on the advantages and disadvantages of each synthesis route and main applications. Along with the conventional methods like sol-gel, thermal decomposition, combustion, co-precipitation, hydrothermal, and solid-state synthesis, several unconventional methods, like sonochemical, microwave assisted combustion, spray pyrolysis, spray drying, laser pyrolysis, microemulsion, reverse micelle, and biosynthesis, are also presented. MFe2O4 (M = Co, Cu, Mn, Ni, Zn) nanosized ferrites present good magnetic (high coercivity, high anisotropy, high Curie temperature, moderate saturation magnetization), electrical (high electrical resistance, low eddy current losses), mechanical (significant mechanical hardness), and chemical (chemical stability, rich redox chemistry) properties that make them suitable for potential applications in the field of magnetic and dielectric materials, photoluminescence, catalysis, photocatalysis, water decontamination, pigments, corrosion protection, sensors, antimicrobial agents, and biomedicine.

scholarly journals Structural and Electrical Properties of Barium Strontium Cobaltite Nanoparticles Synthesized by Wet Chemical Methods

2018 ◽  
Vol 778 ◽  
pp. 151-157
Author(s):  
Tanveer Akhtar ◽  
Omer Farooq ◽  
Muhammad Anis-ur-Rehman
Keyword(s):  
Electrical Properties ◽  
Sodium Hydroxide ◽  
Sol Gel ◽  
Synthesis Methods ◽  
Strontium Nitrate ◽  
Temperature Dependent ◽  
Chemical Methods ◽  
Barium Strontium ◽  
Wet Chemical ◽  
Co Precipitation

Barium strontium cobaltite (Ba0.5Sr0.5CoO3−δ) nanoparticles were synthesized by using without water and surfactant (WOWS) sol-gel method, co-precipitation method and composite mediated hydrothermal method (CMHM). Co-precipitation synthesis was carried out for 0.4 M precursors solutions of strontium nitrate Sr (NO3)2, cobalt nitrate hexahydrate Co (NO3)2·6H2O and barium nitrate Ba (NO3)2 and with the sodium hydroxide NaOH as precipitating agent, sol-gel synthesis was done using ethylene glycol as precipitating agent and the CMHM synthesis was done using sodium hydroxide and Potassium hydroxide (NaOH-KOH) as reactants and precipitating agents at 180 °C for 65 min. Calcination of the synthesized samples was done at 830 °C for 02 hours. Pellets of calcined powder was sintered at 850 °C for 20 minutes. X-ray diffraction (XRD) study was used to find the structural parameters (crystal structure, crystallite size and phase purity). The observed phase transformation of pure barium strontium cobaltite monoclinic to orthorhombic structure was found after heat treatment. Crystallite sizes were calculated by using Scherrer’s formula. Temperature dependent (100 to 600 °C) dc conductivities of the sintered pellets were measured and found to be increased with the successive increase in measuring temperature. Temperature dependent (100 to 600 °C) impedances of all samples synthesized through wet chemical methods at fixed frequency of (10kHz) was also measured and compared. The structural and AC/DC electrical properties were correlated to different synthesis methods. The synthesized samples can be thought as an electrode material for intermediate temperature range solid oxide fuel cells (IT-SOFCs).

Epitaxial Growth of Sr0.3Ba0.7Nb2O6 Thin Films Prepared by Sol-Gel Process

1999 ◽  
Vol 606 ◽  
Author(s):  
Keishi Nishio ◽  
Jirawat Thongrueng ◽  
Yuichi Watanabe ◽  
Toshio Tsuchiya
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Epitaxial Growth ◽  
Raw Materials ◽  
Substrate Surface ◽  
Sol Gel ◽  
Tungsten Bronze ◽  
Monomethyl Ether ◽  
Tetragonal Tungsten Bronze ◽  
Sol Gel Process

AbstructWe succeeded in the preparation of strontium-barium niobate (Sr0.3Ba0.7Nb2O6 : SBN30)that have a tetragonal tungsten bronze type structure thin films on SrTiO3 (100), STO, or La doped SrTiO3 (100), LSTO, single crystal substrates by a spin coating process. LSTO substrate can be used for electrode. A homogeneous coating solution was prepared with Sr and Ba acetates and Nb(OEt)5 as raw materials, and acetic acid and diethylene glycol monomethyl ether as solvents. The coating thin films were sintered at temperature from 700 to 1000°C for 10 min in air. It was confirmed that the thin films on STO substrate sintered above 700°C were in the epitaxial growth because the 16 diffraction spots were observed on the pole figure using (121) reflection. The <130> and <310> direction of the thin film on STO were oriented with the c-axis in parallel to the substrate surface. However, the diffraction spots of thin film on LSTO substrate sintered at 700°C were corresponds to the expected pattern for (110).

Effects of Wet Chemical Oxidation on Surface Functionalization and Morphology of Highly Oriented Pyrolytic Graphite

2020 ◽  
Author(s):  
Mikhail Trought ◽  
Isobel Wentworth ◽  
Timothy Leftwich ◽  
Kathryn Perrine
Keyword(s):  
Surface Functionalization ◽  
Functional Group ◽  
Pyrolytic Graphite ◽  
Surface Oxidation ◽  
Chemical Oxidation ◽  
Synthesis Methods ◽  
Acid Solutions ◽  
Highly Oriented Pyrolytic Graphite ◽  
Wet Chemical ◽  
Surface Morphologies

The knowledge of chemical functionalization for area selective deposition (ASD) is crucial for designing the next generation heterogeneous catalysis. Surface functionalization by oxidation was studied on the surface of highly oriented pyrolytic graphite (HOPG). The HOPG surface was exposed to with various concentrations of two different acids (HCl and HNO3). We show that exposure of the HOPG surface to the acid solutions produce primarily the same -OH functional group and also significant differences the surface topography. Mechanisms are suggested to explain these strikingly different surface morphologies after surface oxidation. This knowledge can be used to for ASD synthesis methods for future graphene-based technologies.

Peculiarities of improving interbudgetary relations in conditions of authorities’ decentralization

2020 ◽  
pp. 46-54
Author(s):  
Zenoviy Siryk
Keyword(s):  
Economic Development ◽  
Social Development ◽  
Social Services ◽  
The State ◽  
Major Objective ◽  
Formal Approach ◽  
Advantages And Disadvantages ◽  
Local Areas ◽  
And Control ◽  
Different Levels

Ukraine is a unitary state, yet historically various regions, oblasts, districts, and local areas have different levels of economic development. To secure sustainable economic and social development and provide social services guaranteed by the state for each citizen according to the Constitution, the mechanism of redistribution between revenues and expenditures of oblasts, regions, and territories through the budgets of a higher level is used. The paper aims to research the peculiarities of improving interbudgetary relations in conditions of authorities’ decentralization. The paper defines the nature of interbudgetary relations. The basic and reverse subsidies to Ukraine and Lvivska oblast are analyzed. The advantages and disadvantages the communities face at changing approaches to balancing local budgets are determined. Regulative documents that cover the interbudgetary relations in Ukraine are analyzed. Special attention is paid to the problem of local finances reforming, including the development of interbudgetary relations. The scheme of the economic interbudgetary relations system in Ukraine is developed. The ways to improve the system of interbudgetary relations in Ukraine are suggested. The negative and positive aspects, advantages, and disadvantages of the system of interbudgetary relations in Ukraine require the following improvements. 1. It is necessary to avoid the complete budget alignment in the process of budgets balancing by interbudgetary transfers as the major objective. 2. The interbudgetary transfers should be distributed based on a formal approach. 3. The changes have to be introduced to the calculation of medical and educational subsidies in terms of financial standard of budget provision to avoid the money deficit for coverage of necessary expenditures. 4. There is a need to improve interbudgetary relations at the levels of districts, villages, towns, and cities of district subordination. 5. Improvement of the mechanism of targeted benefits provision, their real evaluation, and control for the use of funds.

Metallic Nanoparticle Synthesis by Green Chemistry

2018 ◽  
Vol 11 (6) ◽  
pp. 4287-4294
Author(s):  
Anikate Sood ◽  
Shweta Agarwal
Keyword(s):  
Green Chemistry ◽  
Green Synthesis ◽  
Biomedical Research ◽  
Metallic Nanoparticles ◽  
Nanoparticle Synthesis ◽  
Synthesis Methods ◽  
Metallic Nanoparticle ◽  
Medical Field ◽  
Advantages And Disadvantages ◽  
Gold Silver

Nanotechnology is the most sought field in biomedical research. Metallic nanoparticles have wide applications in the medical field and have gained the attention of various researchers for advanced research for their application in pharmaceutical field. A variety of metallic nanoparticles like gold, silver, platinum, palladium, copper and zinc have been developed so far. There are different methods to synthesize metallic nanoparticles like chemical, physical, and green synthesis methods. Chemical and physical approaches suffer from certain drawbacks whereas green synthesis is emerging as a nontoxic and eco-friendly approach in production of metallic nanoparticles. Green synthesis is further divided into different approaches like synthesis via bacteria, fungi, algae, and plants. These approaches have their own advantages and disadvantages. In this article, we have described various metallic nanoparticles, different modes of green synthesis and brief description about different metabolites present in plant that act as reducing agents in green synthesis of metallic nanoparticles. 

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