The article presents the experimental results of the
study of the concentration dependence of the electrical
conductivity of heterogeneous ion-exchange
membranes that are in contact with solutions of weak
electrolytes - carboxylic acids. It is shown that in this
case the membrane conductivity is higher than the
conductivity of the solution, wherein the conductivity
of cation exchange membranes substantially greater
(by an order of magnitude) than the conductivity of
anion exchange membranes. This fact must be
considered when designing the actual electrodialysis
processes of processing solutions containing organic
ions. The work identified the need to develop modern
ideas about transport and the structural organization of
ion-exchange materials, to describe the structure of the
ion-exchange membranes that are in contact with weak
electrolytes solutions
The article illustrates the results of the research dedicated to finding a method of combining two polymeric materials - ion-exchange membranes having different chemical nature. It shows a method of applying a homogenous film MF 4SK on the surface of the heterogeneous membrane substrate to produce a chemically and mechanically stable asymmetric bipolar membrane. We have selected membrane substrate ensuring the best electrochemical performance
Theoretically and experimentally, we investigated the
process of adjusting the pH of natural water of
hydrocarbonate class electrodialyzer with bipolar
membranes with channel length of 40 cm. We
experimentally measured concentration of
components, pH of the solutions in alkaline and acid
channels of electrodeposition depending on the current
density. The article describes a mathematical model
for long channels; to scale the mass transfer
characteristics of the process there was applied and
verified a method of compartmentalization, which
gave the possibility to calculate the dependence of the
component along the channel length at different
velocities of flow of the solution. Numerical
calculations were compared with experimental data on
electrodialyser of 10 cm and 40 cm length
Macrodeficiency of polymeric materials, including the
pervasive one, is a consequence of the development of
initial microdefects which appear in polymers both
due to external factors and during their processing.
This article solves the task of identification the
interrelation and interdependence of structural
microdefects of various polymeric materials,
consisting in the estimation of the structural
parameters under uniaxial deformation. It is
experimentally shown that the process of changing
microdefects in the material bulk begins to flow more
intensely during deformation of the material, having
anisotropic structures in the bulk. Change of the
parameters of microdefects is not observed compared
to the starting material at small quantities of the
deformation. In the area of deformation corresponding
to the transition of the material from isotropic to
anisotropic state parameters of microdefects do not
depend on the degree of deformation of the sample,
and abrupt changes of the parameters of microdefects
are observed after completing the formation of
anisotropic patterns. It is shown experimentally the
identity of the parameters of microdefects in the bulk
material (rubber-based natural caoutchouc) during
deformation with the quantities of local deformations
at the edge of the artificially created macrodefects.
Under uniaxial deformation more than 280-300% and
the growth of the quantities of local deformations
come out at the edge of the artificially created
macrodefects and normalized linear dimension k and
decrease the total number n of microdefects
The аrticle is devoted to study of adsorption of enzymes, antioxidants contained in horseradish root on starch to create enterosorbent with anti-oxidant properties. For this goal we have studied adsorption isotherm calculated constants, thermodynamic parameters (change of enthalpy, entropy, and isobaric-isothermal potential); sorption kinetics of enzyme-antioxidants on starch and calculate the main characteristics. The method of producing of enterosorbent - antioxidant on based starches has been developed based on the experimental data. The ready sorbent is a white powder having no taste and smell. In biological fluids and water, it is insoluble. The enterosorbent on starch does not dissolve in water and biological fluids. It is the solid component. This enterosorbent can be used to protect the gastrointestinal tract of humans and animals against a wide variety of oxidants and peroxide. The results of this work will form the basis for the study of the antioxidant properties of the resulting enterosorbent. The results showed that during the tests, the enterosorbent on the starch showed good antioxidant properties. It has high antioxidant activity with respect to hydrogen peroxide
Surface energy of polymers determines such
important properties of polymers like wetability,
adhesion, ability adsorption of low molecular weight
substances. Inner organization, the structure of the
polymer and the dynamics of interaction between
macromolecular chains are shown at last. At the same
time, the micro-defects (inhomogeneity) of polymers,
which is an integral part of the structure are changed
during deformation and must contribute to changing
of the surface energy and its components.
This article solves the task of detecting changes in the
parameters of surface energy of polymers under
uniaxial deformation. Data for the quantitative
indicators of the surface properties total surface
energy and its dispersive and polar components are
presented. The calculations showed that the disperse
and polar components of all the samples of polymer
materials are about 98% of the total and, therefore, is
crucial. For the first time experimental data,
illustrating the change of surface energy of polymeric
materials had been obtained, including elastomeric
compositions, when uniaxial deformation. The
relative changes of the surface energy vary from 54.5
per cent to 125 %. A decrease of total surface energy
and its dispersion component is observed during
deformation of polymer samples of different structure
and chemical nature
The article presents the results of studies of changes in
the atomic radii of the elements of the periodic table,
depending on their atomic masses. It is shown that the
appearance of p- and d-orbitals introduces a significant
contribution to the value of the atomic radius, and the
appearance of f-orbitals makes a significantly smaller
contribution to the given value. A radial-mass model of
calculations of atomic radii for the elements of the
Periodic Table was developed. Optimal conditions for
making calculations were chosen. For the first time the
values of atomic radii for elements with the order
number 103-120 are calculated. It is shown that the
values of atomic radii for elements with the order
number 103-120 are in the range from 140 to 335
picometers and regularly change in the period
The article presents the results of studies of changes in
the atomic radii of isotopes of the elements of the
periodic table. With using the mass-radial model of
calculations, the values of atomic radii for isotopes of
chemical elements were obtained. It is shown that the
atomic radius of different isotopes of one element is
different and depends on the mass and radius of the
nucleus. To study the changes in ∆Rav values in the
groups and periods of the Periodic Table of Chemical
Elements, the ∆Rav dependences on the period number
and group number are constructed. It is found that the
values depending on the number ∆Rav period / group
for the d-elements lie in the low ∆Rav values for selements
- in high ∆Rav values, and p-elements - in
average values ∆Rav. It is shown that when the atomic
nucleus is increased by 1 neutron, the atomic radius
increases from 0.01 to 4.76 pm, which is due to the
physical effect inside the atom
The method has been developed of simultaneous
determination of active ingredients of different kinds
of pesticides in biological tissues (fish liver) by
applying HPLC with ultra-violet detection and the
rapid method of QuEChERS sample preparation. We
defined optimum volume and composition of the
reagents for the extraction, time of centrifugation and
ultrasound treatment, the origin and composition of
sorbents that ensure maximum extraction of the
substances studied and further cleanup of interfering
substances. Acetonitrile was used as a solvent. The
extraction was carried out in the presence of a
buffering mixture - trisodium citrate dihydrate and
disodium citrate hemihydrate. Bondesil PSA bulk
sorbents (alkylated amine containing two amine
functional groups - secondary and primary) and C18E
(reversed-phase sorbent based on silica gel with
grafted octadecylsilane groups were used to purify the
extract from coextractable substances (fats, proteins,
sugars, organic and fatty acids, pigments and other
impurities). The degree of extraction of the analyzed
active ingredients of pesticides from the liver of fish
was 79%. The detectable pesticide concentrations
ranged from 0,4 to 0,97 mg/kg. The relative standard
deviation of the analysis results amounted to 0,01-0,14
The article presents the results of the development of
an alternative model for calculating the values of
atomic radius. A formula was derived for calculating
the atomic radius of the elements of the Periodic
System of DI Mendeleev. The optimal calculation
conditions for the proposed model are found. It is
shown that the curve of the dependence of the value of
the correction coefficient x on the atomic number of
the element in form coincides with the dependence of
the ionization energy on the charge number