Microwave Dehydration of Borax: Characterization, Dehydration Kinetics, and Modelling

Abstract

In the present study, borax (Na2B4O7 center dot 10H(2)O) was dehydrated using microwave radiation and the dehydration rate curves were calculated. The kinetic parameters and mathematical constants of several drying models were calculated from the dehydration curve data. The best model was selected using the statistical analyses of R-2, chi(2), and root mean square error. From the best model, the kinetic parameters of the activation energy of dehydration were obtained. The powder X-ray diffraction (XRD) technique was applied to characterize the dehydrated compounds. From the results, borax was dehydrated in 18, 11, 6, and 5 min at 180, 360, 600, and 800 W, respectively. XRD analyses showed that borax was in an amorphous phase after microwave dehydration. The models of Midilli et al., and Page best fitted to dehydration curve data and from these models the activation energy was estimated as 7.6108 and 7.3294 kW g(-1).