Thermodynamic Analysis of Moisture Adsorption of Taraxacum Officinale’ Powder

This work aims to model the adsorption isotherms and study the essential thermodynamic properties of Taraxacum Officinale’ powder during the moisture adsorption phenomenon at three temperatures 30, 40, and 50°C. The results have been determined by the application of the thermodynamics physical principles to the equilibrium data, which are experimentally measured. The estimated values of the isokinetic and harmonic temperatures and the Gibbs free energy change revealed that the sorption process is non-spontaneous and enthalpy driven

Modeling of mass transfer during continuous drying of Urtica urens leaves

Urtica urens is one of the main medicinal plants used in the pharmaceutical industry and traditional medicine. It is necessary to know the process of drying and storage of this product. This work is a contribution to the understanding of the mass transfer mechanisms by modeling the drying process of the Urtica urens leaves. The isothermal diffusive model is based on solving the one-dimensional Fick equation. Moreover, an algorithm of minimization compiled by MATLAB is used in this study to get the optimal parameters of the model. The results showed a reasonably good agreement between the values predicted from the model and the experimental observations. This confrontation has helped to identify the diffusion coefficient and the activation energy of the Urtica urens leaves. The effective diffusivity values changed from 4.94 10-11 to 9.66 10-11  within the given temperature range, and the activation energy was found to be 29.34 . In fact, the proposed model accurately describes, on a macroscopic scale, mass transfer processes in the product

Adsorption measurements and study of temperature and humidity influences on the dandelion leaves’ powder

Medicinal plants are photosynthetic organisms that have potential biological activities thanks to their phytochemical compounds. However, the potential of these activities inhabits due to several factors such as temperature and humidity. This paper presents the results of several experimental studies on moisture adsorption phenomena using experimental design methodology and the gravimetric static method as keys to study the impact of temperature and humidity on the powder of the Taraxacum Officinale leaves as well as modeling the moisture adsorption at different temperatures. Additionally, empirical models are fitted in order to regress the isotherms data and represent the relationship between the equilibrium moisture content of the product and water activity. The analysis of the interaction between these factors is based on experiments, statistical calculations, and the analysis of variance method which allow to verify the fact that the humidity affects the powder stability more than the temperature or their interaction