Dependence of Aluminum Oxide Sorption Properties on Deposition pH Value and Coherent Scattering Region Sizes

The authors synthesized samples of aluminum hydroxide by the method of controlled two-jet precipitation under various conditions, followed by thermal decomposition to aluminum oxides. Correlation between values of sorption capacity, pH and CSR values was ob-served

The ways to improve the energy conversion efficiency in erbium-doped Gd 2 O 3 nanoparticles

The basic requirements for the crystal lattice and defectiveness of Gd 2 O 3 matrix as well as for the concentration of Er 3+ dopants to achieve the enhanced parameters of energy conversion in Gd 2 O 3 :Er nanoparticles are summarized. The obtained data allow to optimize and improve the functional characteristics of Gd 2 O 3 :Er-based down-conversion layers applying in solar cells. © 2018 Institute of Physics Publishing. All rights reserved.The work has been funded by the Ministry of Education and Science of the Russian Federation (Government task №3.1485.2017/4.6)

INVESTIGATION OF THE INFLUENCE OF CONTROLLED TWO-JET PRECIPITATION CONDITIONS ON THE PROPERTIES OF ALUMINUM OXIDE

The authors synthesized samples of aluminum hydroxide by the method of controlled two-jet precipitation under various conditions, followed by thermal decomposition to alumi-num oxides. It was found that the pH value of synthesis significantly affects the physicochem-ical properties of samples

INVESTIGATION OF SORPTION PROPERTIES OF La-DOPED HYDROTATED ZIRCONIUM OXIDE

The influence of La-doping on the sorption properties at high pH of precipitated hydro-tated zirconium oxide was studied

SYNTHESIS OF STABILIZED ALUMINUM OXIDE FOR APPLICATION AS A SUPPORT FOR AUTOMOBILE CATALYST

Today in Russia there is no production of gamma-aluminum oxide for use as part of automobile catalysts. Our technology makes it possible to obtain lanthanum-modified aluminum oxide with the required high specific surface area, thermal stability and developed porous structure.The authors express their gratitude to the company "Ecoalliance" LLC and personally to engineer E.O. Baksheev for assistance in testing samples as part of automotive catalysts. Grant support for the research was provided by the state non-profit organization "Foundation for the Promotion of Innovation"

INVESTIGATION OF THE INFLUENCE OF THE PH VALUE OF HYDROLYSIS ON THE CHANGE IN PARTICLE SIZE DURING PRECIPITATION AND DURING THERMAL TREATMENT

This paper present study of influence of the pH value of hydrolysis on the change in particle size during precipitation and during thermal treatment. The pH value of hydrolysis has a significant effect on particles of hydrated zirconia and on the behavior of powders during heat treatment

Investigation of the Influence of Suspension Stirring Rate on the Properties of Zirconium Dioxide Particles by Controlled Double-Jet Precepitation

The work is aimed at studying the effect of the suspension stirring rate on the properties of zirconium dioxide particles. It was shown that the stirring rate affects the morphology and particle size distribution of the obtained oxides

ИЗУЧЕНИЕ ПРОЦЕССА СООСАЖДЕНИЯ МЫШЬЯКА И СУРЬМЫ ПРИ ОТДЕЛЕНИИ МАКРОКОЛИЧЕСТВ ЖЕЛЕЗА, ХРОМА В ВИДЕ Na3FeF6, Na3CrF6

Theoretical and experimental studies were carried out for the first time in order to determine the mechanism of co-precipitation of arsenic and antimony during their separation from the macro-quantities of iron and chromium in the form of Na3FeF6 and Na3CrF6 sediments. It was found that the application of Dubinin-Radushkevich adsorption isotherm gives the most accurate description of the process. The average free energy of adsorption for As and Sb is 9.6 and 9.7 kJ/mol respectively. Co-precipitation of analytes in the micropores of precipitates occurred as a result of the chemical (ion-exchange) reaction. The possibility of inhibiting this process by introducing a different amount of complexing agent (hydrofluoric acid) was studied. The addition of HF led to the formation of more coarse crystalline precipitates with lower specific surface area and porosity. For the accurate ICP-AES determination of analytes (As, Sb) the molar ratio of precipitating agent / complexing agent (NaF / HF) ≈ 1 should be strictly observed. According to the developed procedure, state standard samples of steels and nickel-based precision alloys were prepared for ICP-AES determination of As and Sb contents. The difference between the found and certified content of analytes did not exceed the permitted deviations given in the corresponding Russian state standards. The ICP-AES method of simultaneous determination of As and Sb contents after their preliminary separation from the main components is recommended for the analysis of materials with high content of Fe and Cr.Keywords: sorption, co-precipitation, determination of arsenic and antimony, inductively coupled plasma atomic emission spectroscopy (ICP-AES), adsorption isotherms, fluorides, matrix componentsDOI: http://dx.doi.org/10.15826/analitika.2017.21.3.001 A.V. Maiorova1, S.Yu. Melchakov1,2, T.G. Okuneva2 , K.A. Vorontsova1, M.A. Mashkovtsev21Institute of Metallurgy of Ural Branch of Russian Academy of Sciences,101 Amundsena st., Yekaterinburg, 620016, Russian Federation2Ural Federal University, 19 Mira st., Yekaterinburg, 620002, Russian FederationВпервые проведены теоретические и экспериментальные исследования с целью определения механизма соосаждения мышьяка и сурьмы при отделении от макроколичеств железа, хрома в виде Na3FeF6, Na3CrF6. Установлено, что использование изотермы адсорбции Дубинина-Радушкевича приводит к наиболее точному описанию процесса. Средняя свободная энергия адсорбции для As и Sb принимает значения 9.6 и 9.7 кДж/моль соответственно. Соосаждение в микропорах осадков происходит в результате химической (ионообменной) реакции. Изучена возможность ингибирования процесса с помощью введения разного количества комплексообразующего агента – фтороводородной кислоты. Ее использование приводит к получению более крупнокристаллических осадков с меньшей удельной поверхностью и пористостью. Для точного ИСП-АЭС определения аналитов необходимо строгое соблюдение мольного соотношения осадитель/комплексообразующий агент (NaF/HF) ≈ 1. По разработанной процедуре к ИСП-АЭС определению содержания As и Sb были подготовлены ГСО состава стали и сплавов прецизионного типа на никелевой основе. Разница между найденным и аттестованным их содержанием не превышает нормативов, приведенных в соответствующих ГОСТах.  ИСП-АЭС методика одновременного определения содержания As и Sb с предварительным отделением основных компонентов рекомендована для анализа материалов с высоким содержанием Fe и Cr.Ключевые слова: адсорбция, соосаждение, определение мышьяка и сурьмы, атомно-эмиссионная спектрометрия с индуктивно связанной плазмой (ИСП-АЭС), изотермы адсорбции, фториды, матричные компонентыDOI: http://dx.doi.org/10.15826/analitika.2017.21.3.00

INVESTIGATION THE EFFECT OF YTTRIUM ADDITIVE ON THE PRECIPITATION OF ZIRCONIUM HYDROXIDE DURING CONTROLLED TWO-JET DEPOSITION

To study the effect of the addition of yttrium to zirconium hydroxide on the granulometric composition of precipitation obtained during controlled precipitation. It is shown that the addition of yttrium up to 15 wt. % leads to an increase in the particle size of zirconium hydroxide during