Carbon dioxide sorption by grains and canola at two CO2 concentrations
1998
Cofie-Agblor, R. | Muir, W.E. | Jayas, D.S. | White, N.D.G.
The sorption of carbon dioxide (CO2) by wheat, barley (hulled and hulless), oats (hulled and hulless), and canola was determined at constant volume by exposing 250 g of seed to two initial CO2 concentrations of 49 and 70% (by volume) in 500 ml glass flasks for 144 h. Moisture contents ranged from 12 to 18% (wet basis) for the cereal grains and 10% for canola; temperatures tested were 20, 25 and 30 degrees C. Carbon dioxide uptake by all grains increased asymptotically with increasing exposure time at all test temperatures and initial CO2 concentrations. The calculated amount of CO2 sorbed at equilibrium decreased linearly with increasing temperature from 20 to 30 degrees C at both initial concentrations. The sorption of CO2 was most rapid in canola at 20 degrees C, attaining sorption equilibrium in 24 h compared with 98% of equilibrium amount sorbed in 144 h in oats at 20 degrees C. At similar moisture contents (m.c.), CO2 sorption was greatest in hulless oats at all temperatures and both initial concentrations and the maximum amount sorbed was 492 mg CO2/kg hulless oats at 12% m.c. and 20 degrees C, whereas sorption was least in hulless barley and hulless oats at 18% m.c. and 30 degrees C. For wheat and hulless oats, sorption decreased with increasing moisture content from 12 to 18%, whereas for hulless barley it increased initially from 12 to 14.8% m.c. and then decreased as moisture content increased further. At 25 degrees C, the amounts of CO2 sorbed at equilibrium by both hulless barley and barley were not significantly different (P > 0.05) but the amounts sorbed at equilibrium by hulless oats and oats were significantly different.
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