Elena N. Gryaznova

Colloid stability of iron compounds in groundwater of Western Siberia

The paper reports on experimental modeling of the colloid system composition in natural groundwater. Iron hydroxide is found to be the main component of natural colloid systems. It is shown that silicon compounds and dissolved organic substances (DOS) stabilize iron hydroxide (III), forming a stable colloid system, and preclude coagulation. The presented results suggest that CaCl2 and AlCl3 electrolytes affect the coagulation stability of synthesized model colloid solutions.

Influence of the modification process on the properties of AlOOH nanofibers

A procedure of bulk modification of aluminum oxhydroxide AlOOH during synthesis using manganese(II) ion as the modifying agent was studied. The physicochemical properties of the modified AlOOH fiber were examined. It was found that the presence of manganese(II) ions in solution affected the composition of the products of the reaction between aluminum nanopowder and “liquid water.” The phase composition of the reaction products was examined by X-ray diffraction and differential thermal analysis techniques. It was shown that, for solutions with the manganese ion concentration varying from 0.02 × 10−3 to 40 × 10−3 mol l−1, the degree of amorphicity and the proportion of the AlOOH phase tended to increase. A modification mechanism involving the participation of manganese ions in the AlOOH nanofiber growth process was proposed.

Developing Nanomaterials with Given Properties Based on Aluminum Oxyhydroxide

This paper reports about the method of modified nanomaterials. The aluminum oxyhydroxide was modified by manganese ions (II) during the synthesis. It was shown that modified aluminum oxyhydroxide has new function properties such as catalytic properties. It was shown that the modified aluminum oxyhydroxide with the high concentration of manganese ions (II) could be used in the reaction of the oxidation of methane.

Removal of Iron Colloid Substances from Aqueous Solutions Using Pulsed Corona Discharge

Pulsed electric discharge has been used for the removal of iron colloid substances from aqueous solutions. The residual concentration of organic substances in aqueous solution depends on the pulse repetition rate. The maximum decrease in organic substances concentration was observed at the pulse repetition rate of 800 pps. Comparison of the results obtained for iron colloid solutions containing humic substances and solutions of humic subtances with no colloids shows that the highest removal efficiency of organic substances was obtained when no iron and silicon ions were present in the solution. The results of our experiments suggest that pulsed electric discharge treatment for the removal of organic substances from natural waters is more efficient at an after-treatment stage, after precipitation of colloid substances.

Study the properties of activated carbon and oxyhydroxide aluminum as sorbents for removal humic substances from natural waters

The present work relates to the problem of high-quality drinking water supply using processes of adsorption on activated carbon and aluminum oxyhydroxide for removal humic- type organic substances. Also the paper reports on sorbtion properties of the activeted carbon Norit SA UF and oxyhydroxide aluminum for removal humic substances. It was found out that the maximum adsorption capacity of activated carbon to organic substances is equal to 0.25 mg/mg and aluminum oxyhydroxide is equal to 0.3 mg/mg. It is shown that the maximum adsorption capacity of activated carbon Norit SA UF to iron (III) ions is equal to 0.0045 mg/mg and to silicon ions is equal to 0.024 mg/mg. Consequently, the aluminum oxyhydroxide has better adsorption characteristics in comparison with the activated carbon for removal of humic substances, iron and silicon ions. It is associated with the fact that activated carbon has a large adsorption surface, and this is due to its porous structure, but not all molecules can enter into these pores. Therefore, the fibrous structure of aluminum oxyhydroxide promotes better sorption capacity. The presented results suggest that activated carbon Norit SA UF and aluminum oxyhydroxide can be used as sorbents for removal humic substances or other organic substances from groundwater and natural waters.

Influence of concentration modifier on the structure and functional properties of aluminum oxyhydroxide modified

Studying the properties of nanomaterials is an important task, but nanomaterials with desired properties is a promising direction. The aim of this work is to investigate the influence of the value of the concentration of the modifier (ions Mn2+) on the structural and functional properties of modified aluminum oxyhydroxide. In this paper, using methods such as the X-ray diffraction studies, differential thermal analysis, electron microscopy, chromatography. The paper found that increasing the concentration of the modifier result in significant changes in the morphology, the appearance of metallic aluminum, which is well seen on X-ray data samples. The influence of thermal effects on a modified aluminum oxyhydroxide argon. Set the phase transition temperatures in the synthesized samples. It is shown that with increasing sodeozhaniya manganese in the composition of the synthesized samples decreases the value of specific surface area. Study of the functional properties showed that the synthesized material has catalytic properties in the oxidation of methane. It is shown that the effective sample is a sample with a manganese content of 2.7 wt. %. By XRD results calcined in air samples modified aluminum oxyhydroxide was shown that only in the sample with a manganese content of 2.7 wt. % MnAl2O4 phase is formed, which is catalytically active phase.

Influence of the content of Mn 2+ on the phase composition of the precursor of MnO x -Al 2 O 3 catalyst and the catalytic activity in the oxidation reaction of methane

The influence of the concentration of Mn2+ in a solution for the hydrolysis of nanosized aluminum powder on the phase composition of the precursor and the content of manganese in samples of aluminum hydroxide is studied. Stages of the formation of catalysts from the precursors are studied by means of synchronic thermogravimetric (TG)-differential scanning calorimetry (DSC) analysis and X-ray phase analysis (XPA). The influence of the number of manganese ions in aluminum hydroxide on the phase composition and catalytic properties of MnOx-Al2O3 systems in the reaction of the deep oxidation of methane is also studied. It is shown that an increase in the concentration of manganese ions in the solution for hydrolysis raises the content of unreacted aluminum and X-ray amorphous hydroxides in the precursors of the catalysts. It is established that the phase composition of the catalyst and the catalytic activity in the reaction of the deep oxidation of methane depend on the content of manganese in the precursor.

The Influence of Manganese Amount in Oxyhydroxide of Aluminium – Precursor of MnOx-Al2O3 Catalysts on Catalytic Activity in Reaction of Oxidation of C1-C3 of Hydrocarbons

The authors have synthesized nanofibrous aluminum oxyhydroxide (AlOOH), modified with different amounts of manganese ions (II), which is the precursor for methane deep oxidation catalysts. It was shown that the catalytic activity of the manganese-based system obtained depends on manganese amount and thermal activation conditions. It is approved that as the catalyst for deep oxidation of hydrocarbons the system with manganese content of 10.5 wt. % is the most perspective despite the fact that the oxidation rate of methane is lower in it than in the catalyst with Mn content of 5.7 wt. %. As opposed to the catalyst with Mn content of 5.7 wt. %., where the aluminium oxide is in metastable form (s-Al2O3), the catalyst with manganese content of 10.5 wt. % contains in its structure a thermodynamically and thermally stable α-Al2O3 phase.

Influence of the type of electric discharge on the properties of the produced aluminium nanoparticles

The effect of the method of aluminum nanopowder production on the aluminum products with water reaction is described. It has been established that the interaction of aluminum nanopowder prepared by the electric wire explosion, the phase composition of the reaction products mainly consists of boehmite (AlOOH) and has a fibrous structure. Therefore, that boehmite (AlOOH) can be used for modification of polymer membranes. The modified membranes can be used as water treatment from the impurity of formed true solutions according to adsorptive mechanism, and from colloidal nanometer and micron particles according to the mechanism of mechanical separation of particles depending on sizes.

Effect of Humic Substances and Silicon Ions on Stability of Iron Hydroxide (III) Nanoparticles

The paper reports on experimental modeling of the colloid system composition in natural groundwater. It is shown that the stability of iron hydroxide nanoparticles relates to the presence of silica and humic substances. It was found out the molar ratio of iron/silicon/organic substance is equal to 1/7/2, where stable iron (III) hydroxide nanoparticles form. The iron hydroxide nanoparticle size ranging from 30 to 600 nm was determined. It characterizes the steady state of the colloidal system.