Equilibrium Moisture Content of Untreated and Treated Rice Husk

Abstract

The adsorption and desorption equilibrium moisture contents of untreated, alkali and acid treated rice husk were studied by static equilibration technique using saturated solutions of various salts in the equilibrium relative humidity range of 11 to 80% and at temperatures of 20, 30 and 40°C. Hysteresis was observed for entire range of relative humidity. Different sorption models, namely, modified Chung-Pfost, modified Henderson, modified Halsey, Smith and modified Oswin were tested to fit the EMC-ERH data. Modified Chung-Pfost was found the most suitable model to describe EMC-ERH relationship for untreated and treated husk. The excess heat of sorption estimated from the Clausius-Clapeyron equation, decreased exponentially with increase in moisture content of samples.