CHARACTERISTICS OF CARBON-DIOXIDE SORPTION BY STORED WHEAT

The sorption of carbon dioxide gas (CO2) by wheat was determined in gl ass flasks at four temperatures (0, 10, 20, and 30 degrees C) and four moisture contents (m.c.) (12, 14, 16, and 18% wet basis). The gaseous concentrations were analyzed by gas chromatography and the vacuum dev eloped from the sorption of CO2 by wheat was measured with a mercury m anometer. The calculated amount of CO2 sorbed at equilibrium was a non -linear function of both temperature and moisture content. Sorption of CO2 by wheat decreased with increasing temperature from 0 to 30 degre es C at 14% m.c., and the initial rate of sorption increased with incr easing m.c. from 12 to 18% at a temperature of 20 degrees C. Sorption was modelled using non-linear regression at two conditions (0-30 degre es C at 14% moisture content and 12-18% moisture content at 20 degrees C). The maximum mass of CO2 sorbed in 60 h was 0.510 g/kg of wheat at 18% m.c. and 0 degrees C and the lowest was 0.224 g/kg at 18% m.c. an d 30 degrees C. A linear relationship existed between the initial CO2 concentration and the concentration after 60 h when 250 g of wheat of 14% m.c. at 20 degrees C was exposed in 500 ml flasks.