Superficial acid-base properties of polymer fibres

Protolytic properties of fine fibre plastics based on polypropylene, polyethyleneterephthalate and polycarbonate were investigated. Acidic (carboxylic, hydroxyl) and basic Lewis sites (esters, carbonates, epoxies) were discovered on fibres surface using IR spectroscopy. The number of active groups of various nature and their pKa values were evaluated by potentiometric titration in aqueous and non-aqueous media. The tested fibres possess a low capacity for both acidic and basic sites on it. The results indicate that all the polymer fibre materials (PFM) due to the presence of carboxyl groups on the surfaces, enable modification of their surfaces with metal nanoparticles, thereby giving them unique properties, e.g., photocatalytic and bactericidal

Investigation of acid-base and sorption properties of surface of metal-ceramic composites

The acid-base properties of the surface of composites based on boron, silicon, and sialon nitrides were investigated by the indicator method of Hammett and Tanabe with spectrophotometric indication. Identification of the surface sites of the composites under study was carried out. On the surface of composites based on boron and sialon nitrides the Lewis base sites dominate, while on the surface of samples based on silicon nitride the Brønsted acid sites. Sorption of dyes and oxalic acid by cermet materials was studied. It is shown that the adsorption activity depends on the nature and amount of surface active sites of the composites

Effects of different fertilizer systems and hydrothermal factors on microbial activity in the chernozem in Ukraine

Groups of microorganisms in soils perform the role of global biogeochemical membrane which provides metabolism of substances and energy between the pedosphere, lithosphere, hydrosphere and living organisms. Сlimate change has resulted in a complex combination of unpredictable changeability of the environment, which is a serious test for the stability and productivity for the natural and anthropogenically transformed ecosystems. Changeability of the hydrothermal factors causes serious changes in the structure and metabolic activity of soil microorganisms, the quality and properties of soil. We studied the impact of hydrothermal factors on the content of carbon, microbial biomass and organic substance in deep chernozem of a natural ecosystem (fallow) and an agroecosystem under different systems of fertilization of winter wheat. A close relationship (r = 0.69–0.79) was determined between the content of microbial biomass in soil and hydrothermal factors (air temperature and moisture). Excessive drought and high parameters of air temperature led to decrease in the content of microbial biomass by 1.5–2.8 times compared to the years with optimum parameters of hydrothermal regime (HTC = 1.0). Leveling out the impact of high temperatures on the productivity of the soil microbiota occurs at a sufficient amount of moisture, and also available nutrients. Drought (HTC = 0.4) and excessive moisture (HTC = 2.0) following heightened air temperatures reduce the release of СО2 from soil. Fallow soil usually has a high content of microbial carbon in the organic compounds of soil (Сmic/Сorg was 2%). In the agroecosystem, there was recorded a decrease by 26–32% of the Сmic specific share in the content of the organic compound of the soil compared to the natural analogue. With organic and organic-mineral systems of fertilization, an increase in Сmic/Сorg parameter occurs and the soil parameters become close to the soil of a natural ecosystem. The calculated ecological coefficients of the orientation of microbial processes in soil indicate a possibility of a balanced functioning of the microbial group and introducing organic and organic-mineral fertilizers, creating optimum conditions for the productivity of winter wheat

Formation of the structure of microbiocenoses of soils of agroecosystems depending on trophic and hydrothermal factors

Ground soil, as the product primarily of the activity of microbiota, is under the permanent influence of ecological and anthropogenous factors. Soils are especially subject to pressure in agroecosystems, which increases due to the considerable fluctuation of climate system parameters. Using graph analysis, we have estimated the results of multiyear monitoring research on the functioning of microbiocenoses of three soil types in agroecosystems depending on the fertilizing and hydrothermal mode. It enabled us to detect peculiarities of formation of the structure soil microbiocenoses and to better understand ecologically important relations between functional groups of microorganisms in the soil depending on action of different factors. It has been determined that neither application of organic and mineral fertilizers into chernozem nor action of hydrothermal factors (temperature air and humidity) is a crucial characteristic of changing in the structure of its microbiocenosis. Microorganisms-producers of exopolysaccharides, which have a strong relationship with all trophic groups of microorganisms as they are their structural components, turned out to be the main block constructing factor, which is due to their strong influence on total content of microbal mass in soil. For soil of agroecosystems with dark-grey type of soil characteristic of content of total biomass of microorganisms is a basis for block constructing gremium, which affirms the state of microbiocenosis and processes occurring there under the action of researched biotic and abiotic factors. Microbiocenosis of sod-podzolic soil, unlike the other researched types of soils, reacted distinctly on applying of fertilizer and depended on the action of hydrothermal factors. Contrast in the range of hydrothermal regime caused a chaotic character of interaction between the basic characteristics in microbiocenosis of sod-podzolic soil with appearance of a direct and mediated relationship among them. Regardless of changes in hydrothermal factors , interactions between characteristics of total microbial mass content, eutrophic microorganisms, which use mineral and organic forms of nitrogen, and producers of exopolysaccharides were stable. It has been proved that estimating of ecological state of soil and influence of applicable agromeasures on it should be conducted according to the indices of total microorganism biomass content in the soil and correlation between the number of microorganisms which form the graph gremium

Metal-ceramic composites for photocatalytic oxidation of diclofenac in aqueous solution

Photocatalytic activity of metal‐ceramic composites synthesized by self‐propagating high‐temperature synthesis (SHS) is investigated in the processes of degradation of diclofenac (DCF). Optical properties of the composites were studied, and the band gaps of ceramic matrix semiconducting components were calculated from the absorbance spectra. The effect of the phase composition, UV irradiation duration, the nature and quantity of the activator (H2C2O4 and H2O2) on the degree of oxidation destruction was investigated. The best catalytic performance (98–99 % DCF degradation) was achieved with the combination of heterogeneous boron nitride and SiAlON based composites and a homogeneous photo‐Fenton system. However, DCF decomposition with a minimum number of intermediates was achieved using boron nitride‐based composites. Effective degradation of diclofenac in water! Iron‐containing composites capable of absorbing UV radiation and creating conditions in the presence of hydrogen peroxide and oxalic acid for homogeneous photocatalysis are proposed. Deep degradation occurs with simultaneous oxidative destruction processes of diclofenac according to the principle of heterogeneous and homogeneous photocatalysis

Investigation of acid-base and sorption properties of surface of metal-ceramic composites

The acid-base properties of the surface of composites based on boron, silicon, and sialon nitrides were investigated by the indicator method of Hammett and Tanabe with spectrophotometric indication. Identification of the surface sites of the composites under study was carried out. On the surface of composites based on boron and sialon nitrides the Lewis base sites dominate, while on the surface of samples based on silicon nitride the Brønsted acid sites. Sorption of dyes and oxalic acid by cermet materials was studied. It is shown that the adsorption activity depends on the nature and amount of surface active sites of the composites

Superficial acid-base properties of polymer fibres

Protolytic properties of fine fibre plastics based on polypropylene, polyethyleneterephthalate and polycarbonate were investigated. Acidic (carboxylic, hydroxyl) and basic Lewis sites (esters, carbonates, epoxies) were discovered on fibres surface using IR spectroscopy. The number of active groups of various nature and their pKa values were evaluated by potentiometric titration in aqueous and non-aqueous media. The tested fibres possess a low capacity for both acidic and basic sites on it. The results indicate that all the polymer fibre materials (PFM) due to the presence of carboxyl groups on the surfaces, enable modification of their surfaces with metal nanoparticles, thereby giving them unique properties, e.g., photocatalytic and bactericidal