Moisture Desorption Studies on Polymer Hydrated and Vacuum Extruded Bentonite Clay Mat

Abstract

Moisture desorption observations from two bentonite clay mats subjected to ten environmental zones with individually different combinations of laboratorycontrolled constant temperatures (between 20 آ°C and 40 آ°C) and relative humidity (between 15% and 70%) are presented. These laboratory observations are compared with predictions from mathematical models, such as thinlayer drying equations and kinetic drying models proposed by Page, Wang and Singh, and Henderson and Pabis. The quality of fit of these models is assessed using standard error (SE) of estimate, relative percent of error, and coefficient of correlation. The Page model was found to better predict the drying kinetics of the bentonite clay mats for the simulated tropical climates. Critical study on the drying constant and moisture diffusion coefficient helps to assess the efficacy of a polymer to retain moisture and control desorption through water molecule bonding. This is further substantiated with the Guggenheim–Anderson–De Boer (GAB) desorption isotherm model which is presented.