Mathematical modeling of supercritical CO2 extraction of Monteverdia aquifolia Mart. Biral leaves: Simple models approaching

Abstract

The supercritical extractions of Monteverdia aquifolia leaves were conducted using neat CO2 at different temperatures, CO2 flow rates, and pressures. The highest yield was obtained at 300 bar, 6 mL min-1, and 50 °C. In this condition, extraction kinetics were obtained using mixtures of supercritical CO2 with ethanol and ethyl acetate. Other studies have proven that leaves are a good source of bioactive and antioxidant compounds. In this way, seeking to better understand obtaining these extracts via the supercritical method, simplified mathematical models were tested regarding their performance to predict the extraction kinetics. Equilibrium isotherms obtained were analytically solved and coupled to a mass balance in the extractor resulting in five simplified models that describe the extraction kinetics. The accuracy of the models was tested in the prediction of the experimental yield and compared to the results of the classic Sovová model. Results obtained demonstrated All five simplified models were able to describe the experimental supercritical extraction, still provide insights, and conduct procedures, to solve problems or optimize a situation. The Halsey-type equilibrium model was the most accurate, even when compared to the Sovová model, with an R2 of 0.981 and a relative mean deviation of 9.7%. Considering that M. aquifolia extracts are already a reality in the herbal medicine industry, the data reported here may contribute to the dissemination of the extraction methodology, as well as to the more effective acquisition of the extract, with its biological effects preserved.