Open AccessThermophysical characterization of the powder resulting from the solar drying of the Moringa oleifera leaves
Author(s) -
Codjo Goudjinou,
Clément Ahouannou,
Gédéon Chaffa,
Mohamed M. Soumanou
Publication year - 2017
Publication title -
international journal of engineering, science and technology andb. lagos
Language(s) - English
Resource type - Journals
ISSN - 2141-2839
DOI - 10.4314/ijest.v9i4.4
Subject(s) - moringa , desorption , thermodynamics , equilibrium moisture content , gravimetric analysis , chemistry , characterization (materials science) , atmospheric temperature range , water content , gibbs free energy , materials science , analytical chemistry (journal) , chromatography , adsorption , organic chemistry , sorption , food science , nanotechnology , physics , geotechnical engineering , engineering
This paper presents the results of thermophysical characterization of the powder resulting from the solar drying of Moringa oleifera leaves. The desorption isotherms of the powder, are determined by the gravimetric static method. The models of B.E.T, Smith, Henderson, Iglesias and GAB are used for the smoothing of the experimental points. The Clausius-Clayperon and Gibbs-Helmholtz equation are used for the determination of thermodynamic properties. The isotherms obtained are with type II. The theoretical curves of GAB present a better similarity with the experimental curve at 55°C. The monolayer moisture content (Xm) is 6.32 and 7. 24 % at 30° C; 5.13 and 6.3% at 35 °C; 5.1 and 5.9 % at 45 °C; 4.22 and 4.66 % at 55 °C respectively for BET and GAB models. Isosteric and entropic heats are more important for low values of moisture content. The activation energy of desorption of the powder in the range of temperatures tested is -10.1009539 kJ/mol. Isokinetic temperature (Tβ) and the mean harmonic temperature (Thm) are respectively 301.2435K and 300.12342K and the free energy (ΔGβ) is 302.18 J/mol. The desorption process of the Powder is non-spontaneous and is done by controlled mechanisms enthalpic.Keywords: Moringa oleifera, Thermophysical characterization, Desorption isotherm, Thermodynamic properties, Modelization