POTENTIAL THEORY IN ANALYSIS OF EQUILIBRIUM DATA
FOR SUPERCRITICAL ADSORPTION
L. Czepirski, B. Laciak
University of Mining and Metallurgy, Faculty of Fuels and Energy,
al. Mickiewicza 30, 30-059 Cracow, Poland
High pressure adsorption is of particular use for the characterization of microporous materials. Low temperature adsorption on such materials is frequently complicated by excessive equilibration times due to activated diffusion. The use of adsorbates with small kinetic molecule diameter at temperatures above the critical temperature help to alleviate this problem. p>
Examples of adsorption isotherms for active carbon – gases systems at supercritical temperatures are presented.
The evaluation of some correlations that describe adsorption equilibria was carried out and the hypothesis that equilibrium data could be represented by the potential theory was tested.
Application of potential theory to the systems under study results in temperature – invariant characteristic curves. Using the molar volumes of gases in adsorbed state as an affinity coefficient to each adsorbate, it was demonstrated that characteristic curves for various adsorbates on a given adsorbent at different temperatures are superimposable on single reduced characteristic curve.
Experimental isotherms were also interpreted by the use of the Dubinin – Radushkevich equation. All of the D-R plots show linearity which demonstrates the possibility of application of D-R equation for analysis the microporous structure of carbonaceous adsorbents.
Modification of the Dubinin – Astakhov equation is given and discussed. The proposed form of D-A equation is preserved and physical background of its parameters is modified in accordance with the behavior of the adsorbate at supercritical temperature.
The equilibrium data can be directly related to gases separation to provide essential for contribution process modeling, such as pressure swing adsorption accomplished by selective adsorption.
Development of the modified sorbents
for extraction of ions of heavy metals
from liquid solutions
I. Dedenko1, I. Samodumova1, S. Dedenko1, G. Telbiz2,
O. Shvets2, V. Il’in2, F. Bobonich2
1Scientific-Research Center "Sorption",
Tereshchenkivska st. 17 V, 01004 Kyiv, Ukraine
2Institute of Physical Chemistry, Ukrainian National Academy Sciences,
Nauky avenue 31, 03028 Kyiv, Ukraine
Among environmental problems of last millenium one of the most significant is growing of loading on the ground in connection with development Continue Reading »
THE EFFECT OF ADSORBED VAPOURS ON GRINDING
ABILITY OF HARD COAL
B. Buczek, L. Czepirski
University of Mining and Metallurgy, Faculty of Fuels and Energy,
al. Mickiewicza 30, 30-059 Cracow, Poland
The effect of adsorbed methanol, ammonia and benzene on grinding efficiency of hard coals of different rank was studied. Methanol and ammonia show the largest effect, whereas the presence of benzene decreases the grinding efficiency for all types of coal.
The phenomenon of the impact of adsorption of vapours and gases on the mechanical properties of solids has been known. Rebind Continue Reading »
OLIGOMERIZATION OF THE VINYL MONOMERS
ON THE SURFACE OF ALUMINIUM-CONTAINING SILICA
V.V. Brei, S.I. Levytska, T.V. Chernyavskaya, L.S. Dzyubenko
Institute of Surface Chemistry, Ukrainian National Academy of Sciences,
General Naumov st. 17, 03164 Kyiv, Ukraine,
e-mail: brei@alfacom.net
Vapor-phase polymerization of vinyl monomers on the surface of dispersed oxides is a promising method for obtaining modified fillers for polymers. Using IR spectroscopy, thermal gravimetry, and field ionization mass spectrometry techniques study has been made of oligomerization of some Continue Reading »
SELECTIVE SEPARATION OF BORATE IONS IN WATER
WITH THE USE OF A HYDROUS ZIRCONIUM OXIDE
V. Atamaniouk, T. Mal’tceva, V. Beljakov
V.I. Vernadskii Institute of General and Inorganic Chemistry, Ukrainian National Academy of Sciences, Palladin avenue 32-34, 03680 Kyev, Ukraine
Ukraine possesses only hydrous mineral raw boron reserves. There are underground mineral waters in Carpathians and the Crimea and brines of some lakes. Boric acid concentration in Carpathian mineral waters varies in range 40–530 mg/dm3 and brines of Sivash Lake contain 13 – 35 mg/dm3 of boron. On the other hand, the Continue Reading »
ADSORPTION OF IONIC AND NONIONIC POLYMERS
AT METAL OXIDE/SOLUTION INTERFACE; STRUCTURE
OF THE ADSORPTION LAYERS
S. Chibowski, M. Wiśniewska, M. Paszkiewicz
Faculty of Chemistry, Maria Curie-Sklodowska University,
Maria Curie-Sklodowska sq. 3, 20-031 Lublin, Poland
e-mail:schibows@hermes.umcs.lublin.pl
An influence of the molecular weight of the polymer, its functional groups and pH of the solution was studied on the adsorption and structure of adsorption layers at metal oxide – solution interface. Two ionic polymers were used: polyacrylic Continue Reading »