Hysteresis in the cyclic adsorption of acetone, ethanol and ethyl acetate on activated carbon

Citation
L. Gales et al., Hysteresis in the cyclic adsorption of acetone, ethanol and ethyl acetate on activated carbon, CARBON, 38(7), 2000, pp. 1083-1088
Citations number
20
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
CARBON
ISSN journal
0008-6223 → ACNP
Volume
38
Issue
7
Year of publication
2000
Pages
1083 - 1088
Database
ISI
SICI code
0008-6223(2000)38:7<1083:HITCAO>2.0.ZU;2-Q
Abstract
This paper describes the adsorption behaviour of three solvents (ethyl acet ate, ethanol and acetone) on BASF activated carbon at various temperatures (15-80 degrees C). The adsorption isotherms show hysteresis which persists to very low pressures (Low Pressure Hysteresis, LPH). After prolonged outga ssing (<10(-2) mbar) at 473-523 K we found that LPH still remains. This LPH is more pronounced for ethyl acetate at higher temperatures. Due to its im portance on Pressure Swing Adsorption (PSA) units design and operation we d iscuss the adsorption behaviour when adsorption/desorption cycles are appli ed. We concluded that after approximately five cycles the system reaches wh at we called 'limiting isotherm' where adsorption and desorption branches c annot be distinguished within experimental error. This isotherm is independ ent of system history if a sufficiently low pressure and/or a sufficiently high pressure is used for cycling and in these conditions the adsorbent has higher capacity than when fresh. Also the Langmuir equation correlates qui te well with the limiting isotherms. (C) 2000 Elsevier Science Ltd. All rig hts reserved.