Papers by Keyword: Chemical Process

Abstract: The article provides information about the history of heterogeneous catalysis development. The new aerosol nanocatalysis technology is shown as perspective world nanotechnology. It took up to 20 years to fully understand the technology of aerosol nanocatalysis based on the experimental results obtained. This technology became known to the world from 1996 to the present. The article contains the history of the development of catalysis and technology of aerosol nanocatalysis. The results of research on aerosol nanocatalysis technology were monitored, taking into account its application in industry. Aerosol nanocatalysis technology has been proven successful for environmentally chemical transformations. Industrial and household waste disposal processes using this technology can be called waste-free. The article analyzes the main principles of aerosol nanocatalysis technology and traditional heterogeneous catalysis. The main technological parameters of aerosol nanocatalysis technology are considered. A study of chemical transformations using the technology of aerosol nanocatalysis in a fluidized and vibrating bed was carried out. A SWOT analysis was conducted comparing the technologies of traditional heterogeneous catalysis and aerosol nanocatalysis. Aerosol nanocatalysis technology is promising for the chemical, oil refining and other industries. The ecological condition of industrial and household waste processing technology is considered resource-saving. Aerosol nanocatalysis technology has no analogues in the world. The technological scheme of aerosol nanocatalysis technology is simple. It has been established that this scheme can be applied both for stationary and mobile installations. It has been found that aerosol nanocatalysis technology can transform chemical substances with any aggregate state.

Abstract: Banana peel is a low-cost resource that can be used in a wide range of chemical and industrial processes. The novelty of this research is the use of dehydrated and sieved banana peel to remove mercury from water. The main objective of this research is to evaluate the capacity of the banana peel as an adsorbent capable of removing mercury from contaminated water. It has been shown to be an efficient, low-cost, and environmentally friendly process because banana peel is an environmental waste. To determine the ability of the banana peel to adsorb mercury, the following variables were considered: Hg concentration in water (10, 20, 30, 40, 50, 60, 70, 80, 90 and 100 ppb), particle size of the banana peel (100, 150, 200, 250 and 300 microns), quantity of banana peel per 125 ml of solution contaminated with Hg (2 and 5 grams), the contact time was (20, 40 and 60 minutes); it was not necessary to modify the pH of the solutions to obtain high % of mercury removal. The minerals and fatty acids present in the banana peel were also analyzed to improve the interpretation of the adsorption results. A higher adsorption capacity of mercury was perceived with a banana peel sieved at 150 microns; the results are consistent with other research works such as Cd (II) adsorption according to Azarpira et al. [1] where absorption is improved by decreasing the particle size of the filter material. The effectiveness of bioadsorption depends on the initial concentration of mercury ions and the filter material, the particle size of the filter material, the contact time between the mercury ions and the filter material and the pH (although in this project it is not this variable has been intervened). This study demonstrates that the banana peel used as an adsorbent is very efficient and inexpensive for removing mercury from wastewater. It became possible to demonstrate that the amount of Hg adsorbed per unit mass of absorbent increases with increasing initial Hg concentration in contaminated water, as in other metals [1]. The results of this study have confirmed the viability of using banana peel as an effective alternative for removing mercury from mercury-contaminated waters. Future studies will help to evaluate the economic use of this bioadsorbent and the identification of the main active elements it possesses in mercury adsorption. This study will allow a deeper understanding of the mercury absorption process and will verify the potential possibilities of methods to improve the adsorption process.

Abstract: The behavior of С₅₆ fullerene when heated in a nitrogen atmosphere at a pressure of 10⁵ Pa was studied using computer thermodynamic modeling. The modeling consisted in a complete thermodynamic analysis of the system using the TERRA software package, which is one of the most developed and efficient ones that implements such thermodynamic calculations. Experiment temperature ranges are from 273 to 3373 К. Based on the calculated data, a graph of the carbon balance in the С₅₆-N₂ system was constructed, the ongoing physicochemical processes were described, divided into four classes: sublimation, dissociation in the gas phase, chemical reactions occurring in the gas phase, dissociation and chemical reaction in the gas phase. Temperature intervals of reactions are identified. The equilibrium constants of the reactions are calculated and described, as well as the coefficients of these constants are found using the least squares method. The temperature interval of thermal stability of the condensed C₅₆ fullerene and C₅₆ vapors is defined. This work is one of the series of works on the properties of nanoparticles, in the future it is planned to study the thermal properties of higher fullerenes. The data obtained can be used to determine the explosive and fire hazardous properties of fullerenes as a dispersed solid.

Abstract: This article discusses the modern methods of physico-chemical properties of glass manufacturing, through the use of a wide spectrum of glass-forming. Description of the implementation of the staged methods of chemical-technological processes of silicate formation, implying the lowest energy consumption, in connection with the transition to the processing of secondary raw materials.

Abstract: The examination of the main machining methods applied in manufacturing processes from machine building and based on material removal from workpiece highlights essentially the existence of distinct processes able to generate material. An analysis of certain machining methods able to develop processes of material removal from workpieces was initiated by taking into consideration the principle machining schema and the capacity of generating machined surfaces. One concluded that within distinct machining processes, various phenomena are applied in order to obtain material removal from workpiece.

Abstract: The content of total and soluble elements in different soil profiles of Carex meyeriana mire wetland changed in different seasons, and moved in deep horizon of soil. The correlation among each element in soil profiles was different. As far as the element content of Carex meyeriana fraction is concerned, nitrogen in laminae, phosphorus and kalium in vagina were the highest content, respectively. The accumulated quantity of elements in laminae was the highest in May and account for 22%, that of August was the lowest with 1%; the content of total kalium in May was the lowest and account for 15%, the lowest occurred in September with a percent of 5%; the content of total phosphorus in August was the highest accounting for 31%, and that of September was lowest with 2%.

Abstract: Nanocrystalline TiO₂ powders were obtained at a low temperature between 50 and 80 °C by a hydrolysis of TiCl₄ in a mixed solution of distilled water and alcohol. The as-synthesized TiO₂ powders were characterized by X-ray diffraction analysis, transmission electron microscopy, and UVvisible absorption spectroscopy. Effects of the reaction temperature and the NH₄F concentration on the formation of the nanocrystalline TiO₂ powders were investigated. Results indicate that the reaction temperature greatly affects the particle size of the as-synthesized samples, and the NH₄F concentration has a great effect on the phase structure of the as-synthesized samples. In addition, the photocatalytic activities of the as-synthesized samples for rhodamine B were also measured, and it is found that the sample synthesized from the NH₄F concentration of 30 mM exhibits a higher photocatalytic activity than the P25 powder due to a high surface area and a pure anatase phase.

Abstract: In the present work, vertical ZnO nanorods (NRs) were grown onto ITO substrates by a simple two step chemical process at relatively low temperature by using successive ionic layer absorption and reaction method (SILAR) and chemical bath deposition (CBD) method. The investigated on n- ZnO/ p-Polythiophene heterojunction device have been fabricated with ZnO nanorods. Structural analysis reveals that the grown ZnO NRs exhibit (002) reflection with higher intensity, indicating that the ZnO NRs grown in c-axis orientation. FESEM image shows the surface morphology of grown ZnO nanorods was of hexagonal wurtzite structure whose diameter varies from 200 nm to 1μm. Room temperature Photoluminescence exhibited strong UV emission at ∼386 nm and a negligible green band confirms the presence of very low concentration of oxygen vacancies in the well-aligned ZnO nanorods. The current–voltage (I –V) characteristics of the heterojunctions show good rectifying diode characteristics. These results indicate that hybrid device fabricated from solution process is a promising approach for future light-emitting diodes (LEDs) devices.

Abstract: With the development of concrete industry, the necessity for utilizing waste materials and decreasing overall energy consumption is becoming increasingly obvious. Fly ash and granulated blast-furnace slag, which are used as blends of Portland cement, are waste materials produced in electric and energy industry, and concretes made with them can have properties similar to ones made with pure Portland cement at lower cost per unit volume. By using blended Portland cement, both ecology benefit and economic benefit can be achieved. Due to the pozzolanic reaction between calcium hydroxide and blended components, compared with ordinary Portland cement, hydration process of blended Portland cement is more complex. In this paper, based on a multi-component hydration model, a numerical model which can simulate heat evolution process of blended Portland cements is built. The influence of water to cement ratio, curing temperature, particle size distribution of cement paste and blended Portland material, and cement mineral components on heat evolution process is considered. The prediction result agrees well with experiment result.

Abstract: Malaysia mainly produced low quality kaolin and the paper describes the development of a chemical process to produce high purity alumina and zeolite from this mineral. Selective leaching technique was applied to remove 45% of the Al2O3 content in kaolin. The high purity alumina produced shows similar characteristic to the commercial product. An alkaline fusion stage was then carried to transform the kaolin mineral into zeolite. Identification of the crystalline phase by XRD shows that it consists of both zeolite P and hydroxysodalite.