The extraction of resinoids from St. John's wort (Hypericum perforatum L) was studied in a series of two papers. While the first part dealt with the effects of the operating conditions on the yield of resinoids (total extract) and process optimization, the mathematical models of extraction kinetics were analyzed in the second one. The extraction was carried out using an aqueous solution of ethanol (70 and 95 % v/v) at the hydromodulus (plant material to solvent ratio, w/v) of 1:5 or 1:10. The plant material was disintegrated and divided into three fractions (particle mean size 0.23, 0.57 and 1.05 mm). The temperature was 25, 50 or about 80?C (boiling temperature). Three models were applied for modeling the extraction kinetics: a model based on the film theory, a model based on unsteady state diffusion through solid material and the empirical Ponomarev equation. Because of its physical basis, the relative simplicity and good fitting of the experimental data, the model based on the film theory could be proposed for mathematical modeling of solid-liquid etraction processes.U drugom delu rada prikazuju se rezultati analize kinetike ekstrakcije rezinoida kantariona (Hypericum perforatum L). U prvom delu je analiziran uticaj radnih uslova na prinos ukupnog ekstrakta i optimizacija procesa ekstrakcije, u ovom, drugom delu, analiziraju se razliciti modeli koji mogu da se upotrebe za definisanje kinetike ekstrakcije rezinoida kantariona. Za modelovanje kinetike ekstrakcije rezinoida kantariona koriscena su tri dvoparametarska modela: model zasnovan na teoriji filma, model zasnovan na teoriji nestacionarne difuzije kroz cvrst materijal i empirijski model Ponomarjeva. Svi radni uslovi i dobijeni eksperimentalni rezultati o prinosima ekstrakta i rezinoida, koji su iskorisceni pri analizi kinetike ekstrakcije, navedeni su u prvom delu rada.
CITATION STYLE
Veljkovic, V., & Milenovic, D. (2002). Extraction of resinoids from St. John’s wort (Hypericumperforatum L): II. Modeling of extraction kinetics. Hemijska Industrija, 56(2), 60–67. https://doi.org/10.2298/hemind0202060v
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