Biomedical Engineering Reference
In-Depth Information
shown a certain degree of similarity among the adsorption properties
of the studied adsorbent. The analysis of the data evidences a significant
increase of oxygen sorption, especially on fullerene, at temperatures
low but notably higher than the oxygen liquefaction temperature.
This phenomenon can be exploited to accumulate oxygen in
systems for singlet oxygen generation based on the photo-
desorption from the surface of solid fullerene-containing samples,
for applications in biology, medicine, and laser technology.
We should also note a very effective oxygen liquefaction on
fullerene at 77 K, which is two times higher than that the one
on activated carbon and an order of magnitude higher than for
forastralene. This specific capability of fullerene to accumulate gases
in a liquid state can be used in several technological fields.
Some experiments have shown a substantial dependence of the
sorption capability of a material on the method of its preliminary
preparation, in particular on its degree of pulverization. For instance,
according to control measurements, the sorption of oxygen on
activated carbon subjected to a special milling process similar to that
performed for fullerene C
in Ref. [35], increased approximately five
times. This factor is less important for astralene, whose structure
is, in many respects, determined by aggregation processes, and for
which the required grinding cannot be performed mechanically.
In concluding the present analysis of the researches regarding
oxygen and nitrogen adsorption on fullerenes and polyhedral multi-
layered carbon nanostructures (astralene), we would like to give at
least a brief analysis of the results of similar studies on hydrogen
adsorption on the same types of adsorbents. The advisability of such
an addition is related to the paramount importance of the researches
on hydrogen adsorption that, along with oxygen adsorption, is
proposed for a variety of advanced applications, as indicated in the
introduction to this chapter.
Up to now only few data on hydrogen adsorption on fullerenes
and different polyhedral multi-layered carbon nanostructures
have been obtained. Among the reported researches it is to be
noted a special method for preparation of fullerene-based sorption
material proposed in the USA Patent N6113673 [50]. Preparation
of this material is carried out by means of the usual press-assisted
compression of a fullerene powder with variously shaped granules
and their subsequent polymerization by heating under a high-
pressure rare gas atmosphere. The authors of this patent stated high
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