The experimental stand based on oxythermography method to research of sorption capacity of porous thermostable sorbents

Abstract

The main emphasis of this work is development of a new evaluation method of sorption capacity
and the creation of the experimental equipment to testing a new method of investigation of porous solids
(sorbents). At the heart of this method is a programmable heating the porous solid in a flow of non-reactive
gas for instance argon, with subsequent cooling the sample to ambient temperature, whereas the sample has
been blowing by gas mixture (in this case, air with a known amount of oxygen) or pure gas, whereas the gas
is sorbed by the given sample. The sample is rapidly moved into the high temperature region, which is in a
flow on a non-reactive gas, where this sample is heated to a specified temperature, after reaching sorption
equilibrium. In this way the gas is desorbed from the volume of the investigated sorbent. With the help of
sensor is the high-temperature solid electrolyte cell (HTSEС) based on zirconia for instance oxygen sensor,
the desorbed oxygen from the given sample is recorded. The area integral of cruve of oxygen is the analyticalsignal of this method. The consecutive order of process desorption-adsorption-desorption can be carried out
as a cyclic process.
The experimental stand has created to realization and test of the new proposed method. This stand
based on the existing thermal oxidation equipment which is named oxythermography. Oxythermography able
in some cases to provide meaningful competition with the classical methods in such parameters as the time
and cost of the analysis of a single sample. It must be pointed out that the surface of the porous material
sample preparation that is to say calcination samples to remove previously adsorbed substances in a high
temperature furnace is carried out also using the oxythermography. An estimation of the minimum amount of
oxygen (2·10‒8 g) was made on this showing on measurement of the analytical signal related to time.
Klinoptilolity is natural porous materials two different fields - Khonguruu and Holinskoe were studied to test
the developed method. The average value of the mass of oxygen and a mean-squared departure for zeolite
from the deposit was (7.70±0.3)∙10‒7 g Khonguruu, and (31.3±1.1)∙10‒7 g for Holinskogo have been
determined according to six consecutive measurements. The obtained results enabled to calculate the mass of
oxygen adsorbed per 1 gram of the sampling materials, which is to say their sorption capacity. The results
exhibit a difference in the amount and rate of released oxygen for the studied sorbents of two deposits with
the same weight. Therefore, with the help of created experimental stand based on thermal oxidation
equipment, the possibility in principle of the studying of porous materials with proposed approach has been
exhibited.