Environmental Engineering Reference
In-Depth Information
CNF enabled one to conclude that the nickel particles active for hydrogenation
of light alkenes reside on the zigzag faces. More characterization work is needed
to substantiate these interesting claims. Others have carried out, by far, the most
extensive work on CNF as carbon support material. A driving force for exploring
CNF supports was related to the replacement of active carbon as support for liquid
phase catalysis. For the CNF support, no shift of the PSD is apparent, whereas
with an activated carbon (AC) support, severe attrition is apparent. They compare
the PSD after ultrasonic treatment of the CNF and of the AC support. Clearly, AC
displays a much broader PSD with, moreover, a significant number of fines. Nano
composite electrodes made of carbon nanofibers and paraffin wax were charac-
terized and investigated as novel substrates for metal deposition and stripping
processes. Since CNFs have a much larger functionalized surface area compared
to that of CNTs, the surface active groups to volume ratio of these materials is
much larger than that of the glassy-like surface of CNTs. This property, combined
with the fact that the number and type of functional groups on the outer surface of
CNFs can be well controlled, is expected to allow for the selective immobilization
and stabilization of bio molecules such as proteins, enzymes, and DNA. Addi-
tionally, the high conductivity of CNFs seems to be ideal for the electrochemical
transduction. Therefore, these nano materials can be used as scaffolds for the con-
struction of electrochemical biosensors [64-68].
Compared with conventional ELISA-based immunoassays, immune sensors
are of great interest because of their potential utility as specific, simple, label-free
and direct detection techniques and the reduction in size, cost and time of analy-
sis. Due to its large functionalized surface area and high surface-active groups-
to-volume ratio. Hydrogen storage is an essential prerequisite for the widespread
deployment of fuel cells, particularly in transport. Huge hydrogen storage ca-
pacities, up to 67%, were reported. Unfortunately such astonishing values could
not confirmed by other research teams worldwide. Volumetric and gravimetric
hydrogen density for different storage methods, some reviews provide basics of
hydrogen storage on carbon materials, the types of carbon materials with potential
for hydrogen storage, the measured hydrogen storage capacities of these mate-
rials, andbased on calculations, an approximation of the theoretical achievable
hydrogen storage capacity of carbon materials [91, 92].
1.1.8 ACTIVATED CARBON NANOFIBERS (ACNF): PROPERTIES AND
APPLICATION
Electro spinning, a simple approach to make very fine fibers ranging from nano to
micro scales, is attracting more attention due to the high porosity and high surface
area to volume ratio of electros pun membranes. These properties contribute to
potential applications of electros pun membranes in carbon and graphitic nanofi-
ber manufacturing, tissue scaffolding, drug delivery systems, filtration and rein-
forced nanocomposites. The researchers also tried poly (amic acid) as a precursor
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