J. ESMAILI, M. R. EHSANI
62
Figure 5. The breakthrough curves of the sorbent prepare
at optimum conditions during CO2 adsorption.
4. Conclusions
The sorbent capacity for carbon dioxide capture from a
gas stream is important for the industrial application of
solid sorbents. The present investigation was carried out
to study combined effects of the initial solution concen-
tration, impregnation time, calcination temperature, and
calcination time on the sorbent capture capacity using a
Box-Behnken design under the Response surface metho-
dology (RSM). The obtained results demonstrate that
sorbent capacity increased with increasing the initial so-
lution concentration and impregnation time. Sorbent ca-
pacity has a maximum point for variation of calcination
temperature and time and further increases of these vari-
ables lead to decrease of sorbent capacity. However,
ANOVA analysis as well as 3D surface plots revealed
that initial solution concentration has the greatest effect
on sorbent capacity. On the basis of the results it can be
concluded that RSM presents an excellent tool which
enables the evaluation of interactions and competitive
effects in multivariable systems and reduces the number
of needed experiments in contrast to the classical method
of changing one variable at a time.
The optimized values obtained for initial solution con-
centration, impregnation time and calcination step tempe-
rature and time were 32.3 wt%, 13.4 hr, 367˚C and 4.1 hr,
respectively, with the predicted maximized response of
sorbent capture capacity (78.66 mg CO2/g sorbent). Stu-
dy on other sorbent characterization such as mechanical
strength require for application of this procedure for pre-
paration of industrial sorbents.
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