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Adsorption equilibrium of α‐amylase in aqueous solutions
Author(s) -
Bautista L. Fernando,
Martínez Mercedes,
Aracil José
Publication year - 1999
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690450411
Subject(s) - adsorption , freundlich equation , chemistry , langmuir , endothermic process , ionic strength , aqueous solution , equilibrium constant , langmuir adsorption model , chromatography , ion exchange , thermodynamics , inorganic chemistry , organic chemistry , ion , physics
The influence of pH, ionic strength and temperature on the equilibrium of adsorption of α‐amylase from Aspergillus oryzae on a hydrophobic (Duolite XAD‐761) and an anion‐exchange (Duolite A‐568) polymer‐based adsorbent was studied by moment analysis of the chromatographic peak responses in HPLC. The adsorption isotherms were also measured in batch experiments at different temperatures. Both systems show a nonlinear equilibrium within the concentration range studied, and the results were fitted to both the Langmuir and Freundlich equations. Enthalpies and entropies of adsorption were estimated from the equilibrium adsorption constant obtained both by moment analysis and by the limit region of the Langmuir isotherm corresponding to Henry´s law. The results show that the process of adsorption of α‐amylase on the hydrophobic resin was exothermic, while the anion exchange process is endothermic.