3 research outputs found
Adsorption of Four Representative Biological Compounds onto Graphite Nanofibers
The present study investigates the adsorption of four
compounds
important in carbon adsorption hemoperfusion. Graphite nanofibers
(GNFs) having different carbon plane orientations have structural
features that make them potentially attractive in this application
compared to activated carbon. Generally, adsorption capacity increased
in the order of ribbon > herringbone > platelet fiber types.
All fibers
were poor adsorbents for creatinine. Herringbone and platelet fibers
had sorption capacities less than 25% of activated carbon for all
adsorbates on a mass basis. Except for vitamin B12, behavior of ribbon
fibers was similar; vitamin B12 adsorption was nearly 50% greater
than activated carbon on a mass basis. In contrast, on the basis of
surface area, all of the fibers were comparable to or outperformed
activated carbon for the adsorption of all adsorbates. This suggests
that in addition to BET surface area, interactions between adsorbate
and exposed basal planes in carbon are important in determining adsorption
capacity. Chemical treatment with hydrochloric acid or with urea followed
by thermal treatment did not significantly change the fiber surface
area, micropore volume, or equilibrium adsorption. Nitric acid treatment
of herringbone and ribbon fibers slightly decreased the surface area
but did not enhance adsorption, whereas this treatment degraded platelet
fibers