This paper presents the results of a study of the change in the stability of Fe2O3/NdFeO3 nanocomposites when exposed to aggressive media over a long period of time. The main purpose of these studies is to investigate the mechanisms of degradation and corrosion processes occurring in Fe2O3/NdFeO3 nanocomposites, as well as the influence of the phase composition on the properties and degradation resistance. According to the X-ray phase analysis, it was found that the variation of the initial components leads to the formation of mixed composition nanocomposites with different Fe2O3/NdFeO3 phase ratios. During corrosion tests, it was found that the dominance of the NdFeO3 phase in the composition of nanocomposites leads to a decrease in the degradation and amorphization rate of nanostructures by a factor of 1.5–2 compared to structures in which the Fe2O3 phase dominates. Such a difference in the degradation processes indicates the high stability of two-phase composites. Moreover, in the case of an aqueous medium, nanocomposites dominated by the NdFeO3 phase are practically not subjected to corrosion and deterioration of properties. The results obtained helped to determine the resistance of Fe2O3/NdFeO3 nanocomposites to degradation processes caused by exposure to aggressive media, as well as to determine the mechanisms of property changes in the process of degradation. The results of the study of the absorption capacity of Fe2O3/NdFeO3 nanocomposites in the case of the purification of aqueous media from manganese and arsenic showed that a change in the phase ratio in nanocomposites leads to an increase in the absorption efficiency of pollutants from aqueous media.
The article assesses the dynamics of desertification based on changes in the area of moving sands in the territories of the villages Issatay, Zineden, Maykomgen, Miyaly Zhaskairat over the past 17 years based on the processed data of remote sensing satellite images. It should be noted that the research area is located almost on the border of the semi-desert and desert zones, which within Kazakhstan occupy 57.7% of the territory. Ecosystems of these arid territories are very vulnerable to impacts, especially in modern conditions of climate change, reduction of water resources and active anthropogenic development. It should be noted that land degradation has a serious socio-economic impact on the standard of living and health of the population, especially on socially vulnerable sections of the rural population.
The earlier studies about the efficiency of the main tillage showed that at the overall tillage for Kochia prostrate sowing don not guarantee the uniformgermination throughout the field, both in space and in time. It is due to theunsatisfactory water-physical conditions of the subsurface soil where seeds lie. Taking it into account, a farming system is being developed. It is aimed at accumulating and preserving moisture in the soil strips (10-15 cm wide, repeatedin 45-50 cm in the virgin soil), treated with a help of the method of a surface excavation of a loose soil layer with the formation of a solid compacted bed where seeds of Kochia prostrate are placed. The research results showed a high efficiency of harvesting the upper loose soil layer in strips with a width of 10-15 cm to a depth of 5-8 cm with the creation of a highly compacted solid seed bed, without conducting basic soil cultivation. In this variant, the optimum completeness of seedlings and a rather high yield of forage by fodder mass of Kochia prostrate were obtained 3.12 g / ha on average over three years. Earlier, before the development of this research, Kochia prostrate with annual sowing provided only 2 years of full-fledged germination from five years of sowing. Then as a result of the conducted research, a number of years providing full-fledged germination has reduced to 4 years of sowing.
A system of agriculture is being developed to accumulate and preserve moisture in soil strips (5-10 cm wide, 5 cm deep, repeated every 50-55 cm in virgin soil untouched by vegetation), treated by surface raking of the loose seedbed layer to form a solid compacted bed, where an ideal condition for seed germination is created. With a favorable combination of weather and climatic conditions, this variant provides an optimal fullness of seedlings and a fairly high fruit-bearing weight of 3.9 t/ha on average for four years, including 4,8 tons in 2019. However, in extraordinary 2019-2020 crop year with extremely low precipitation (2,7 times lower than average annual norms), with the warm winter and spring (100 more than the average annual norm), incredibly intense droughts and dust storms (average of 18-19 days a month vs 4-5 mean annual norm) wind erosion dominated and dictated terms everywhere: furrows, sown with seeds of Summer Cypress were completely covered with drifts of dust with a thickness of 2-3 cm, under which the seedlings could not break through to the surface of the soil and died. In the cultivar keeping nursery, where seeds were sown directly without tillage and 15 PCs/m2 of seedlings were obtained only in the dust-inspired areas that make up one third of the area (400 m2).
Research work on the radical improvement of pastures with the sowing of prostrate rods (Kochia prostrate) against the background of plowing the soil to the depth of 20-22 cm has been carried out in the CIS countries since 1936 to this day. Despite the long-term study, in modern conditions, there are no industrial sowing of prostrate rods in Kazakhstan. The repeated attempts to introduce rods into production have failed. The long-term experiments (more than 50 years) have shown that Kochia prostrate does not sprout every year (approximately, two years out of five years, and then in places and sporadically). In one place full-fledged seedlings are provided, and in another place they are absent. That is, tillage does not provide the required efficiency. In this review, on the basis of original studies, the development of soil conditions for the growth of Kochia prostrate during soil cultivation is detailed. As known, when plowing, the upper fertile soil horizon is thrown down and it is buried by the less fertile, more structureless soil of the lower horizons. This, firstly, leads to the development of a hard crust impenetrable by Kochia prostrate sprouts and, secondly, when dry, solid soil blocks are formed under the seeds, impermeable by hypocatilny roots of Kochia prostrate. Therefore, sprouts of either die during dump plowing, or full-fledged shoots are not formed on it. The current dead-end situation with soil cultivation can be corrected by developing a new theoretical concept and, on its basis, developing a technology for soil cultivation and Kochia prostrate cultivation.
The aim of this work is to evaluate the application of NiFe2O4 nanoparticles with spinel structures as the basis of catalysts for the purification of aqueous media from pollutants such as manganese and arsenic. The interest in these catalysts is due to their ease of production and high absorption efficiency, which, together with their magnetic properties, allow the use of nanoparticles for a long time. The sol–gel method, followed by thermal annealing of the samples at different temperatures, was proposed as a method for the synthesis of spinel nanoparticles. The choice of the annealing temperature range of 200–1000 °C is caused by the possibility of estimating changes in the structural properties and the degree of nanoparticles crystallinity. During the study of structural changes in nanoparticles depending on the annealing temperature, it was found that in the temperature range of 200–800 °C, there is an ordering of structural parameters, while for samples obtained at annealing temperatures above 800 °C, there is a partial disorder caused by the agglomeration of nanoparticles with a subsequent increase in their size. According to the results of the studies on the purification of aqueous media from pollutants, it was found that the greatest absorption efficiency belongs to nanoparticles annealed at 500–700 °C, with the purification efficiency of 70–85%, depending on the type of pollutant. The results obtained from the use of nanoparticles as catalysts for the purification of aqueous media show great prospects for their further application on an industrial scale.