The paper presents evaluation of energy distribution of n-octane and pore-size distribution functions on the alumina oxide surface (e.g. total heterogeneity) of on the basis one experimental
run. the Q-TG mass loss and derivative Q-DTG mass loss curves of n-octane thermodesorption from the alumina oxide sample were made using a hungarian derivatograph with an analyser equipped
with an automatic ultraslow procedure and a special crucible of maintaining the quasi-isothermal heating procedure to increase
the resolution of thermal analysis. a new theoretical and experimental procedure was developed for evaluation of distribution
functions of liquid preadsorbed on the mesoporous surface from special thermogravimetry. An example of the approach to quantitative
description of the energetic and structural heterogeneities of alumina oxide surface is given.
Authors:G. Chądzyński, V. Kutarov, and P. Staszczuk
In this paper the theoretical approach and applications of Cahn ultramicrobalance to kinetic study on the thermal decomposition
of the high-temperature Y1Ba2Cu3O7-x superconductor are presented. Thermogravimetric in situ measurements of oxygen loss from Y1Ba2Cu3O6 samples heated isothermally in a relatively high dynamic vacuum were performed with a Cahn RG electrobalance. Single-phase
orthorhombic samples of composition Y1Ba2Cu3O7-x (highest oxygen content) were synthesized from stoichiometric (1:2:3) mixtures of high-purity Y2O3, BaCO3 and CuO. The original 1:2:3 mixture was prepared by the two-stage procedure described earlier. The crystal structure of the
sample in the original orthorhombic phase was controlled by the X-ray powder method (CuKα radiation) using a Stadi P Stoe diffractometer with a position-sensitive detector. Activation energy is estimated from appropriate
Specific surface area and pore size distribution are determined usually from adsorption isotherms at low temperatures using
nitrogen or noble gases. These are not absolute parameters and the measuring methods are fraught with serious difficulties.
General problems of sorption measurements and recent developments are discussed. To obtain information for practical purposes
these measurements need to be supplemented by investigations of the sorbate/sorbent system used in practice. Results of the
measurement of nitrogen and water vapour adsorption on different materials are compared.
Energetic heterogeneity of adsorbents is conditioned by the differences in topology of adsorption centres, dispersion of pore sizes and other factors. This paper describes theoretical and experimental studies that demonstrate a method for estimation of the energetic heterogeneity of adsorbents by making use of the results from single thermogravimetry Q-TG and Q-DTG curves, recorded under quasi-equilibrium conditions, for preadsorbed liquid on a porous solid surface.
multi-layer adsorption it is common to use standard isotherms. To establish
such isotherms experimental data are required at a wide range of adsorptive
pressure. This paper presents the theoretical and experimental analysis of
the new tδ-method,
which is suitable to predict type II multi-layer adsorption isotherms on the
basis of only two adsorption values, measured in the area of mono- and multi-layer
saturation and of the surface fractal dimension of the adsorbent.
Authors:P. Staszczuk, M. Płanda-Czyż, M. Błachnio, and V. Kutarov
The new method of diffusion coefficient calculations
from thermogravimetry Q-TG data has been presented. Programmed thermodesorption
of polar and apolar liquids from aluminium oxide and montmorillonite-Na and
-La samples in quasi-isothermal conditions has been made. The result from
above method was compared with literature data and good correlation were obtained.