Ionic two-dimensional chromatography as the industrial method
obtaining the metals of the high purity
V. Zadov1, I. Dementyeva2, V. Medvedev3, I. Mlyavyy4
Siberian Technology University, Krasnoyarsk, Russia
Departament ОАО КB "Iskra", Krasnoyarsk, Russia
Company "Technostandart", Krasnoyarsk, Russia
НИС avia construction college, Dolgoprudny, Russia
In the article some crying problems of obtaining the metals of high cleanliness are
examined. Is given the brief analysis of the possibility of using the two-dimensional
chromatography as the possible industrial method of obtaining the chemically pure
Ionic chromatography widely adapts for the analysis of the aqueous solutions,
which contain different cations and anions. The superficially modified polymers are
used as the fixed phase. They have low ion-exchange capacity.
The surface arrangement of ion-exchange groups is necessary for decreasing the
problems, connected with the diffusion into the depth of ion-exchange layer, which
sharply decreases the dividing ability of column. The decrease of sizes of grains of the
superficially modified polymer increases ion-exchange capacity and sharply increases
the dividing ability, but increases the resistance of layer. This leads to the
chromatography of high pressure.
The application of a one-dimensional ionic chromatography for separation and
cleaning of large quantities of substances is complicated by the periodicity of process
and it does not make it possible to make the continuously working column. Any change
in the flow of eluent leads to imposition and mixing of the divided ions, if they enter the
separation in the form of continuous jet.
Problem can be solved by action on the divided ions of electrical or magnetic field
in combination with the electric current, passed along the column. Both versions lead to
the appearance of force, acting on the moving ion and directed perpendicularly to the
direction of the flow of liquid in the column.
Let us examine the first version. The displacement of ions under the action of
electric field is known in electrochemistry as mobility. Corresponding data for the dilute
solutions are located in the reference books and are given in the form the speeds of the
displacement of ion with the single electric field intensity.
With the potential gradient approximately into 100 volt per meters (two volts at a
distance into two centimeters) the copper ion will move per hour up to the distance in
one-and-a-half centimeter. It is obvious that this displacement in the direction
perpendicular to the direction of fluid flow in the column, which has the annular cross
section of ion-exchange sorbent, makes it possible to derive the zones of the output of
different ions on the different distances from the entrance into the column, in this case
the selection of substances must be achieved through the side of the chromatographic
column. It is necessary to be determined with the type of electrode materials and to
solve for the industrial mastery of method - what precisely electrochemical reactions are
expedient on the cathode and the anode.
The second version is also interesting, since Lorentz force acts to the moving
charge in the magnetic field, moreover its value sharply is differed from electrostatic
forces to the large side. Unfortunately, there is no reference or complete experimental
data on the displacement of the moving ions in the solutions under the action of
magnetic field practically.
The speed of the lateral motion of ion can be estimated on the basis of the equality
of the Lorentz force and resisting forces to the motion of ion, which depend on the
speed of its displacement. This hybrid chromatographic column, has electrodes at the
entrance and the output, which ensure ion flow along the column and magnetic field in
the transverse direction. It can be more effectively for the separation of ions, just as
usual electric motor is more effective than the electrostatic.
At the same time, it is necessary to solve the problem of the separation of the
positive and negative charges, which move under the action of Lorentz force in opposite
directions, and because of the mutual attraction which brake the displacement of each
other. For eliminating this effect is possible the version of the combination of magnetic
separation with the electrical, which was described above.
Thus, continuous two-dimensional chromatography with the application of the
electrostatic, electromagnetic or combined method of the separation of ions is possible
and requires experimental realization. As the divided ions can be used both inorganic
and organic ions, for example amino acid, the latter can be cations or anions depending
on the reaction of medium.