Cyclic fixed-bed operations under moist conditions for the recovery of carbon dioxide from flue gases have been carried out employing K
2CO
3 upported on porous materials. Moisture, usually conta ined 8 1 7% in flue gases, badly decreases the adsorption capacity in the conventional fixed-bed a dsorption technology. However, since potassium carbonate absorbs carbon dioxide in the presence o f water to form potassium hydrogencarbonate (K
2CO
3+CO
2+ H
2O ↔ 2KHCO
3), the moist conditions are rathe r necessary. Deliquecent potassium carbonate should be supported on an appropriate porous material in order to use in fixed-bed operations. A drastic decrease in surface area was observed when K
2CO
2 was supported on the hydrophilic silicagel, reflecting the blockade with K
2CO
3 in micropores, while K
2CO
3was supported on hydrophobic activated carbon without appreciable change in surface area. In th e case of pelleted a-Al
2O
3, potassium carbonate filled up the interstices of nonporous alumina powders. The XRD observations suggest hydrothermal reaction of potassium carbonate with silica g el, resulting in the decrease in CO
2 a dsorption capacity of K
2CO
3-on-SiO
2. On the other hand, reproducible CO
2-uptake was observed for K
2CO
3-on-Carbon. Entrapped CO
2 was recovered reversibly by the decom position of potassium hydrogencarbonate on flashing with steam at 150 200° C.
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