Dear Sir ,
I am performing an experiment for measurement of Adsorption Capacity of Methanol onto Indian ACF. I couldn't get adsorption and desorption properly. What should be the packing density of ACF? What other parameters should I consider for better results. Please give me suggestions.
You can follow the reference cited below for properties of methanol
METHANOL ADSORPTION ON ACTIVATED CARBONS FOR ADSORPTION
HEAT PUMP APPLICATIONS
Jian Sun and Sunita Satyapal
United Technologies Research Center (UTRC)
411 Silver Lane, MS 129-90
East HarO~ord, CT 06108 USA
Summary:
Two activated carbon adsorbents, a coconut shell-based activated carbon (AC) and an activated carbon fiber (ACF), were characterized using nitrogen adsorption
isotherm measurements at 77 K with a Micromeritics ASAP 2010 instrument.
Variations of
Fig.1 i) Pore size distribution of AC powder and ACF;
Fi.2. Exp and calculated nitrogen isotherms for AC powder and ACF (ref 2),
Fig.3 M methanol adsortpion for AC powder and ACF powder.
FIg..4 Heat rate of methanol desorption for AC powder and ACF powder. .
Conclusions: In comparison with AC powder, ACF has --80% higher BET surface area, ---50% higher pore volume, --55% higher methanol adsorption capacity, and --70% higher adsorption heat per gram of carbon adsorbent.
In general, activated carbon fibers have higher BET surface areas and pore volumes compared to activated carbons made from coal or coconut shell. This is because carbon fibers consist of a uniformly sized graphite planar structure. Its smaller geometric size (i.e., the fiber diameter) also allows greater microporosity to develop during steam activation.
Fig.1 The pore size distribution results (Figure 1) show that both samples are microporous (< 20 ]A) with negligible mesopore (20 - 500 A,) and macropore
(> 500 A,) volumes.
Fig.2 The corresponding experimental and calculated nitrogen adsorption isotherms (for modeling, Ref.2) for both samples are plotted in Figure 2. A larger fraction of micropores in adsorbents is desirable to maximize the heat output per pore volume because the enhanced adsorption energy boosts the heats of adsorption.
fIG.3 heat released due to methanol adsorption as a function of time, indicating that both materials have similar adsorption kinetics with a similar sample mass (--0.25 g).
Fig.4;Tthe kinetics of methanol desorption is quite different for both samples The entire desorption period for the AC powder is longer than that for ACF.
Ref.2
2) Sun, J., Rood, M.J. and Rostam-Abadi, M. Carbon'97
Extended Abstract and Program Vol.1 pp. 348 (1997)
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