Abstract
Batch desorption experiments of vitamin E from silica were carried out to study the effects of reaction temperature and agitation rate on the kinetics and equilibrium of desorption. For all systems, it was found that vitamin E desorbed rapidly in the early stages, followed by a much slower release. The two distinct desorption rates might be due to the heterogeneities of the adsorbing surfaces. A first-order two-component four-parameter model described the desorption kinetics well with a coefficient of determination, R2 of >0.97. The rate constants for rapid (krap) and slow (k slow) desorption ranging from 0.51 to 2.23 min-1 and from 0.01 to 0.14 min-1, respectively, depending on reaction temperature and agitation rate. It was found that the krap value increased with increase in reaction temperature, indicating that desorption of vitamin E from silica was endothermic in nature. The desorption rate also increased with increase in agitation rate. Activation energies for the rapid and slow desorption were 38.64 and 73.08 kJmol-1, respectively. It was found that the desorption isotherm can be fitted by the Fruendlich model. Percentage recovery of vitamin E from silica ranged from 70.36% to 98.74%, depending on the experimental variables. The results from this study provided useful information for achieving high recovery of vitamin E during its separation using an adsorption method.
Original language | English |
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Pages (from-to) | 1-7 |
Number of pages | 7 |
Journal | Journal of Food Engineering |
Volume | 64 |
Issue number | 1 |
DOIs | |
Publication status | Published - Sep 2004 |
Externally published | Yes |
Keywords
- Desorption
- Equilibrium
- Kinetics
- Silica
- Vitamin E