Environmental Engineering Reference
In-Depth Information
carbonyls were attached to carbon atoms located on the edges of the fragments. It
was assumed that the structure of the carbon skeleton remained unchanged. Pore
size distributions, determined using the BG method were found not to be greatly
affected by oxidation. Simulated isotherms for Ar, N
2
and CO
2
were calculated
using the GCMC method. For Ar, the effect of oxidation on the isotherm was
relatively small. However, for N
2
and CO
2
there were significant changes in the
isotherms, due to electrostatic interactions between N
2
and CO
2
and the surface
carbonyl groups. As a consequence of this, pore size distributions calculated from
the simulated isotherms for N
2
andCO
2
differed markedly from those originally
determined from the BG method. An important conclusion from this is that ex-
perimental PSDs determined using CO
2
(or using N
2
if there is a large oxygen
content) may be unreliable. A further study looked at the influence of carbon sur-
face oxygen groups on Dubinin-Astakhov equation parameters calculated from
CO
2
isotherms. It was concluded that porosity parameters calculated by fitting the
DA model to experimental CO
2
adsorption data may be questionable. Others have
published a number of other studies in which fullerene-like models have been
used to predict the properties of microporous carbons, but the results summarized
above are sufficient to demonstrate the utility of such models method is compared
with results from the Horvath-Kawazoe method.
1.4 CONCLUSION AND OUTLOOK
This review has attempted to cover a wide range of adsorption activities of porous
carbon (PC), CNTs and its composites and carbon nano structures, which have
been employed so far for the removal of various pollutants from the water and
wastewater. This detailed review presented more discussion about carbon nano-
structures adsorbents, modeling and simulation methods in different sections. The
low cost, high efficiency, simplicity and ease in the up-scaling of adsorption pro-
cesses using PC makes the adsorption technique attractive for the removal and
recovery of organic compounds. The activated carbon modification process has
also been of interest to overcome some of the limitations of the adsorbents. Due
to a large specific surface area and small, hollow, and layered structures, CNTs
and carbon nano structures have been investigated as promising adsorbents for
various metal ions; inorganic and organic pollutants can be easily modified by
chemical treatment to increase their adsorption capacity. There is the huge hope
that nanotubes applications will lead to a cleaner and healthier environment. A
brief summary of these modeling methods is investigating here. In addition two
important simulation method including Monte Carlo and Molecular Dynamic in
this review that by design a simulation cells, dependence to materials and applied
systems and other condition such parameters of models that selected for this simu-
lation of case study, are discussed. New Monte Carlo methods will be devised
and will be used with more powerful computers and applied in PSD calculat-
ing models by assumption adequate simulation cells. The presence of micro and
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