Page 232 - Gas Adsorption Equilibria

218 Chapter 4

3.5 Densimetric-Volumetric Measurements of Binary
Coadsorption Equilibria

For sake of completeness we want to draw the reader’s attention to the fact
that binary coadsorption equilibria with non-isomeric gas components can be
determined not only by combined volumetric-gravimetric measurements (Sect.
2) or densometric-gravimetric measurements (Sects. 3.1-3.4) but also by
volumetric-densimetric measurements without the need to analyze the sorptive
gas phase in a gas chromatograph [4.18]. A schematic diagram of an
installation in which measurements of this type can be performed is given
below, Fig. 4.18, followed by a snapshot of such an instrument which has
been designed and built in our laboratory (IFT PB A 0126/1), Fig.4.19. It
mainly consists on an adsorption chamber (AC) including the sorbent sample
and a magnetic suspension with two working positions only bearing a sinker
(titanium) for gas density measurements. In addition there are storage vessels
for the pure sorptive gas components and auxiliary equipment like a gas
circulation pump, valves, manometers, and thermometers, a vacuum pump and
a gas supply system. All vessels and tubes connecting them should be placed
in a thermostat.

Figure 4.18. Instrument for volumetric-densimetric measurements of binary coadsorption
equilibria of gas mixtures on porous solids without using a gas chromatograph.
The sorptive gas prepared in the system is assumed to be a binary mixture with
known initial molar concentrations © IFT University of Siegen, 2002.