Gallery character of porous space in the STI-type zeolite structure

The existence of a specific gallery type of zeolite framework is confirmed. It has been found that similar to HEU-type, STI-type framework can be represented as a layered structure in which two impermeable to water molecules and exchange cations aluminum-silicate layers, separated by diortho-groups, confined gallery-type of porous free space, which is available for extra-framework components migration in all directions in the plane of the interlayer.

Human-Altered Soils at an Archeological Site of the Bronze Age: The Tyater-Araslanovo-II Settlement, Southern Cis-Ural Region, Russia

This paper presents the results of studying the soils at the archeological site of the Tyater-Araslanovo-II settlement located in the Republic of Bashkortostan, eastern European Russia. The settlement functioned in the 15th–12th centuries BCE (the Late Bronze Age). We compared the soil properties at four sites in the study area: archeological (1), buried (2), affected by long pyrogenic exposure (3), and background site (4). In soil samples, the total carbon content, the fractional composition of humus and organic matter characteristics, alkaline hydrolyzable nitrogen, total phosphorus, mobile phosphorus, potassium, absorbed calcium and magnesium, pH, particle size distribution, basal soil respiration, and optical density were estimated. The study results showed the anthropogenic impact on the archeological site’s soils. The newly formed AU horizon at the archeological site (1), affected by the cattle summer camp, was richer in soil nutrients and agrochemical properties, namely, the content of exchangeable and gross forms of phosphorus, alkaline hydrolyzable nitrogen, and exchange cations of the soil absorbing complex compared to the reference soil (4). For the pyrogenic layer (AU[hh]pyr) from the ancient furnace (fireplace) (3), the mobile and total forms of phosphorus were several times higher than those in the reference soil (4) but inferior regarding other agrochemical parameters. Thus, the activities of ancient people (especially cattle breeding) greatly influenced the properties of the soil.

Research of nanostructural minerals – bentonites used in purification of mineral water from heavy metal ions (Cu2+, Pb2+, Cd2+, Zn 2+)

This paper presents the results of studies on the use of bentonite from the Taganskoye field for purification of mine water from the mining industry from heavy metal ions (MI). It has been established that the use of the thermo-acid-activated form of bentonite clay allows the removal of MI Cu2+, Pb2+, Cd2+, Zn2+ions from mine water by 99.6, 94.7, 98.9, 99.5 %, respectively, which ensures that the maximum permissible concentration of fishery is achieved at selected optimal conditions that were identified on the basis of an active experiment. A comparative analysis of the presented results of mass spectrometry and scanning electron microscopy shows that they are valid and do not contradict the obtained experimental data on the composition of exchange cations and structural characteristics in ultrafine mineral phases of bentonite clay samples of natural and thermo-acid activated forms It has been established that during acid activation of bentonite clays, the structure of montmorillonite is retained upon extraction of up to 80 % of magnesium, iron, and aluminum ions and is destroyed only upon their almost complete extraction.

Effect of fertilizing systems on changing the agrochemical properties of black soil typical under using tilled crops rotation by-products as an organic fertilizer during the crop rotation

In general, the average annual loss of humus was 1.96 t/ha, 1.14 t/ha and 0.24 t/ha, respectively, for zero, first and second fertilizer levels in crop rotation, while the increase for the third level made 0.44 t/ha. At the highest fertilizer rate, total nitrogen reserves in crop rotation increased by 0.89 t/ ha. The annual application of 12 tons of manure + N95P82K72 per hectare of arable land ensured a deficit-free balance of humus in crop rotations and a slight decrease of 2.3 % of ammonia nitrogen in the arable layer over five years, which did not exceed LSD0.05. With the highest fertilizer rate, the ammonia nitrogen content in the black soil typical for five years increased by 2.0 mg/kg in total in crop rotations. The fertilizer rate of 12 t/ha of manure + N95P82K72 stabilized the mineral nitrogen content in the soil and the dose 159 of 16 t/ha of manure + N112P100K86 significantly increased the level in the crop rotation. Increase of available phosphorus content and potassium exchange in soil at the application of 12 t/ha of manure + N95P82K72 was not significant and made 1.0 mg/kg. The highest fertilizer rate significantly increased the content of these nutrients in the typical black soil arable layer. Over five years, exchange acidity at zero, first, second and third fertilizer levels decreased by 0.11, 0.10, 0.16 and 0.22, respectively, with the total for crop rotation of LSD0.05 0.12. Soil hydrolytic acidity for crop rotation at zero and first fertilizer levels increased by 0.15, and at second and third fertilizer levels – by 0.20 and 0.28 mg – eq/100g, respectively. The degree of soil saturation with the bases decreased during the rotation period at fertilized and unfertilized plots, but significant decrease was observed only at application of 16 tons of manure + N112P100K86 per hectare of arable land. The content of calcium exchange cations in the soil only decreased significantly during the rotation period when the highest fertilizer rate was applied annually. No significant deviations were found in the content of magnesium exchange cations in the soil. The crop rotations at unfertilized plots, fertilized with 8 t/ha of manure + N76P64K57, 12 t/ha of manure + N95P82K72 and 16 t/ha of manure + N112P100K86 were 2.35, 3.61; 4.77 and 5.77 t/ha dry matter respectively, 3.21; 5.04; 6.64 and 8.00 t/ ha feed units, 0.296; 0.422; 0.560 and 0.691 t/ha digestible protein at LDS0.05, 0.38; 0.51 and 0.043 t/ha, respectively. Key words: fertilizers, crop rotation, soil, crop, agrochemical properties, rotation period, yield, productivity.

Influence of sodium lignosulfonate on loamy soil and cucumber plants

Sodium lignosulfonate is a water-soluble by-product obtained by the sulfite method of cellulose production. In a model experiment, the authors investigated the effect of sodium lignosulfonate on certain agrochemical parameters of sod-podzolic loam soil and on the physiological parameters of cucumber plant development. Sodium lignosulfonate was added to the soil in concentrations 0 %, 1 %, 2,5 %, 5 % and 10 % of the dry soil weight. The samples were incubated at a constant temperature (23 °С) and a constant humidity of 70 % for 90 days. Adding lignosulfanate to the model soil in small concentrations (1 and 2.5 %) significantly increased the content of potassium (from 169.7 mg/kg in the control to 389.1–431.6 mg/kg, respectively) and exchange cations, but reduced the nitrogen content regardless of the dose. The concentration of Mg, CA and Na increased by 3.9…7.8 times, which had an alkalizing effect on the soil. At a concentration of 2.5 % lignosulfonate, the pH of the salt solution increased by 1.26 units. At the same time, the concentration of the buffer solution significantly increased, which was manifested in the physiological response of plants. Lignosulfonate reduced the accumulation of plant biomass and proportion of roots in the total mass. With an increase in the concentration of lignosulfonate in the soil, the degree of inhibition of growth processes increased. Lignosulfanate did not affect the stomatal regime of leaves and transpiration losses of water, but it reduced the water content in the leaf depending on the concentration. Photosynthetic activity of plants was partially suppressed in conditions of high lignosulfonate content in the soil. Lignosulfonate did not enhance plant tolerance to low temperature.

BACKGROUND PHYSICAL AND CHEMICAL CHARACTERISTICS OF THE SOIL COVER OF THE NORTHERN PART OF THE STATE RESERVE «VERKHNE-TAZOVSKY»

Analytical studies of background soils on the territory of the Yamal-Nenets Autonomous Okrug were Carried out using generally accepted methods in soil science. Low availability of tested soils with organic matter and basic exchange cations is shown. Indicators of heavy metal concentrations, silt and humus content, and sorbents (iron and manganese hydroxides) were obtained.

Synthesis and characterization of clay nanocomposites based on starch

ABSTRACTIn this work, the synthesis of starch-clay nanocomposites was carried out. For this purpose, natural starch was extracted from rice grains and it was characterized by structural and spectrophotometric techniques. Afterwards, it was used as the polymer matrix for the synthesis of nanocomposites crosslinked with different agents: glycerol, citric acid (CA) and sodium trimetaphosphate (STMP). As a reinforcement phase, a natural Mexican clay from the Montmorillonite-type (Mt), was employed, which was modified with a cationic surfactant, hexadecyltrimethylammonium bromide (HDTMA-Br), in order to exchange cations, present in the interlaminar spaces of the raw clay mineral with those of the cationic surfactant; thus, changing its nature from hydrophilic to hydrophobic. Characterization, of both natural and organo-modified clays, was carried out by means of scanning electron microscopy (SEM), to determine the change in morphology between these two minerals; X-ray diffraction analysis (XRD), to obtain the crystalline structure of the organo-modified clay and that of the raw clay mineral (Mt). Also, the Fourier transform infrared spectroscopy (FTIR) was employed to determine materials spectra, and their thermal stability was evaluated by means of the thermogravimetric analysis (TGA). On the other hand, the synthesis of these nanocomposites was performed using different crosslinking agents, glycerol, CA or STMP, in order to identify the effect of them into the final properties of these materials.